Can't get my engine running right

[Eric Drust]

I know there is a ton of info on this subject all over the web, but I am at a total loss. I just don't know what is going on.

I just finished a JAE12 outrigger I started building over two years ago. To power it I chose my Go engine .18 which I took from my RTR boat. The RTR boat ran great with this engine. It would start easy, require minor tweaking on the high speed needle, and would run pretty reliable. I did notice it had minimal low end. If I did not keep the speed up it could sometimes die on me.

Well I brought the JAE to my local lake and gave it a try. Engine started with zero effort, seemed to idle with no problem (without the igniter even), and even was pretty responsive to the throttle. I stuck the boat in the water and it took off like a rocket. After about 100 yards the engine died.

I tried again this time with only about 75% throttle. The boat went a bit farther, maybe 150 yards and died.

I set the needle to run a bit more rich this time. Still no luck, it went even less distance. Went a bit leaner and it went the same distance.

As I tried over and over it went less and less, until it would not even stay running to launch it. Now on the test bench it won't start at all.

Glow plug seems fine, and igniter gets it glowing.

Any ideas what is going on?

Now for the additional information...

The JAE12 is setup different than my RTR boat was. I have a MACS 2.5 header as I did on the RTR, but this one is new and I cut it to approximately the same length as the old one. It now has a Zippkits tuned pipe for .12 engines, and before it had a MACs 2.5 pipe in the RTR boat.

I also am not positive I am running the same glow plug as before. I know at one time it was running its original Go engine plug, and another time I used an OS #8 in it. I have some more #8s I can try, and that was going to be my next step.

Here is the big question though. This engine is a water cooled one, and in the RTR boat it was setup as such. Now in my JAE12 I am not water cooling it. My assumption was with so much of the engine exposed there would be no need for water cooling. However, since this is a water jacket type head, without any fins, I suppose the internal layer against the compression chamber could be overheating and damaging it, even though it is not hot on the outside.

Anyway, sorry for such a long post, but I am beyond discouraged, and need any guidance I can get. I already went ahead and purchased a Zippkits mini sprint, LiPo, charger, motor, radio, and servo to try out electric boats. I have had a lot of R/C stuff over the years, all of which was electric, until I got the RTR nitro boat, and I just don't think I have the comprehension to keep a nitro engine running.

 

[anthony_marquart]

Here are some suggestions

- first hook up a water line. It needs it.

- what fuel are you running? Get some new fuel

-put in a new plug

- are you running back pressure through the tuned pipe? if not put it on.

-take out the fuel system, lines and all. Put it in the sink onder water and blow into it with one side pinched shut. Look for bubbles.. if it bubbles easily fix the leak.

-Clean out the carb needle and lines etc..

It sounds like a fuel delivery problem. Make sure needles are clean, orings in the carb are good etc..

If all these things don'r fix it you probably have bad bearings in the motor,.. or absolutley no compression.

Speaking of compression.. check the head bolts... if they're loose it will act as you describe..

Good luck

I know there is a ton of info on this subject all over the web, but I am at a total loss. I just don't know what is going on.

I just finished a JAE12 outrigger I started building over two years ago. To power it I chose my Go engine .18 which I took from my RTR boat. The RTR boat ran great with this engine. It would start easy, require minor tweaking on the high speed needle, and would run pretty reliable. I did notice it had minimal low end. If I did not keep the speed up it could sometimes die on me.

Well I brought the JAE to my local lake and gave it a try. Engine started with zero effort, seemed to idle with no problem (without the igniter even), and even was pretty responsive to the throttle. I stuck the boat in the water and it took off like a rocket. After about 100 yards the engine died.

I tried again this time with only about 75% throttle. The boat went a bit farther, maybe 150 yards and died.

I set the needle to run a bit more rich this time. Still no luck, it went even less distance. Went a bit leaner and it went the same distance.

As I tried over and over it went less and less, until it would not even stay running to launch it. Now on the test bench it won't start at all.

Glow plug seems fine, and igniter gets it glowing.

Any ideas what is going on?

Now for the additional information...

The JAE12 is setup different than my RTR boat was. I have a MACS 2.5 header as I did on the RTR, but this one is new and I cut it to approximately the same length as the old one. It now has a Zippkits tuned pipe for .12 engines, and before it had a MACs 2.5 pipe in the RTR boat.

I also am not positive I am running the same glow plug as before. I know at one time it was running its original Go engine plug, and another time I used an OS #8 in it. I have some more #8s I can try, and that was going to be my next step.

Here is the big question though. This engine is a water cooled one, and in the RTR boat it was setup as such. Now in my JAE12 I am not water cooling it. My assumption was with so much of the engine exposed there would be no need for water cooling. However, since this is a water jacket type head, without any fins, I suppose the internal layer against the compression chamber could be overheating and damaging it, even though it is not hot on the outside.

Anyway, sorry for such a long post, but I am beyond discouraged, and need any guidance I can get. I already went ahead and purchased a Zippkits mini sprint, LiPo, charger, motor, radio, and servo to try out electric boats. I have had a lot of R/C stuff over the years, all of which was electric, until I got the RTR nitro boat, and I just don't think I have the comprehension to keep a nitro engine running.

 

[SayMikey]

What prop are you running?

 

[Eric Drust]

Thanks guys for the advice.

-I can hook up the water line pretty easily.

-Fuel is 30% and is 2 years old. It worked fine in my RTR boat I ran two weeks ago though, so I figured it is good.

-I can try a new plug

-I have a pressure line from the tuned pipe.

-All fuel lines are new, tank is new, pipe is new. Carb is clean.

-Motor has great compression. It came from a running boat, so I think it is still good.

-Prop is a 440

It is amazing to me how many problems can be solved while “sitting on the can”. This morning prior to going to work I was doing just that, and I think I may have an idea what is going wrong. The less the fuel level in the tank the shorter the run time of the engine, down to the point now where it will not run at all.

Well, on the cover of the JAE12 manual the boat in the photo has very long fuel lines. I don’t remember the photo exactly, but I am pretty sure either the pressure line, or the line to the carb is quite long. So much so it goes down the boat, then comes back up to the tank. I thought this looked pretty ugly, but now I am thinking it was done for some reason due to fuel flow.

My lines are the minimum length they can be. The line from the tank goes down under the engine and back up to the carb. It is at best only 2in long. The pressure line from the tank to the pipe is maybe 10in long.

How long should these lines be?

I am pretty sure I got my tank internally setup right. I used the nylon tubes for it, and bent them such that the pressure line goes up to the bubble on the top of the tank, and the feed line goes to the rear outside corner (assuming right turns only), with a small “V” cut in it, so it can’t be blocked by the walls of the tank.

 

[anthony_marquart]

Well,.. I would still look at the fuel delivery.. Richen up the motor till you have to blip the throttle just keep it running. You should be able to hold the throttle wide open for 2-3 sec before it spins up. This is a good place to start.. launch the boat super rich.. I wise man once told me "boats don't die from being rich"

So open it all up and get a super rich needle. spitting fuel from the exhaust and everything... like you are breaking in a new motor.. are you running a cowl? once I had a cowl that was choking off the carb and it didn't show till I launched it.

Thanks guys for the advice.

-I can hook up the water line pretty easily.

-Fuel is 30% and is 2 years old. It worked fine in my RTR boat I ran two weeks ago though, so I figured it is good.

-I can try a new plug

-I have a pressure line from the tuned pipe.

-All fuel lines are new, tank is new, pipe is new. Carb is clean.

-Motor has great compression. It came from a running boat, so I think it is still good.

-Prop is a 440

It is amazing to me how many problems can be solved while “sitting on the can”. This morning prior to going to work I was doing just that, and I think I may have an idea what is going wrong. The less the fuel level in the tank the shorter the run time of the engine, down to the point now where it will not run at all.

Well, on the cover of the JAE12 manual the boat in the photo has very long fuel lines. I don’t remember the photo exactly, but I am pretty sure either the pressure line, or the line to the carb is quite long. So much so it goes down the boat, then comes back up to the tank. I thought this looked pretty ugly, but now I am thinking it was done for some reason due to fuel flow.

My lines are the minimum length they can be. The line from the tank goes down under the engine and back up to the carb. It is at best only 2in long. The pressure line from the tank to the pipe is maybe 10in long.

How long should these lines be?

I am pretty sure I got my tank internally setup right. I used the nylon tubes for it, and bent them such that the pressure line goes up to the bubble on the top of the tank, and the feed line goes to the rear outside corner (assuming right turns only), with a small “V” cut in it, so it can’t be blocked by the walls of the tank.

 

[Ted buckley]

Thanks guys for the advice.

-I can hook up the water line pretty easily.

-Fuel is 30% and is 2 years old. It worked fine in my RTR boat I ran two weeks ago though, so I figured it is good.

-I can try a new plug

-I have a pressure line from the tuned pipe.

-All fuel lines are new, tank is new, pipe is new. Carb is clean.

-Motor has great compression. It came from a running boat, so I think it is still good.

-Prop is a 440

It is amazing to me how many problems can be solved while “sitting on the can”. This morning prior to going to work I was doing just that, and I think I may have an idea what is going wrong. The less the fuel level in the tank the shorter the run time of the engine, down to the point now where it will not run at all.

Well, on the cover of the JAE12 manual the boat in the photo has very long fuel lines. I don’t remember the photo exactly, but I am pretty sure either the pressure line, or the line to the carb is quite long. So much so it goes down the boat, then comes back up to the tank. I thought this looked pretty ugly, but now I am thinking it was done for some reason due to fuel flow.

My lines are the minimum length they can be. The line from the tank goes down under the engine and back up to the carb. It is at best only 2in long. The pressure line from the tank to the pipe is maybe 10in long.

How long should these lines be?

I am pretty sure I got my tank internally setup right. I used the nylon tubes for it, and bent them such that the pressure line goes up to the bubble on the top of the tank, and the feed line goes to the rear outside corner (assuming right turns only), with a small “V” cut in it, so it can’t be blocked by the walls of the tank.

Eric, I had the same problem with my JAE. So much so, that I was ready to throw the boat on the Freeway that was on the hill above us. I don't know what kind of tank you have, but mine was metal(I made the tank). I've never had problems with my Metal tanks before - and refused to believe that it was the tank. If it is metal/Aluminum or whatever - try a plastic 4 oz. Sullivan to do a test. Larry C. and Dick Dahlhemier pointed me in this direction and it worked. I have also seen where the Nitro in the fuel filter(Skin's-over) the screen. You can check that too.

 

[Ted buckley]

Thanks guys for the advice.

-I can hook up the water line pretty easily.

-Fuel is 30% and is 2 years old. It worked fine in my RTR boat I ran two weeks ago though, so I figured it is good.

-I can try a new plug

-I have a pressure line from the tuned pipe.

-All fuel lines are new, tank is new, pipe is new. Carb is clean.

-Motor has great compression. It came from a running boat, so I think it is still good.

-Prop is a 440

It is amazing to me how many problems can be solved while “sitting on the can”. This morning prior to going to work I was doing just that, and I think I may have an idea what is going wrong. The less the fuel level in the tank the shorter the run time of the engine, down to the point now where it will not run at all.

Well, on the cover of the JAE12 manual the boat in the photo has very long fuel lines. I don’t remember the photo exactly, but I am pretty sure either the pressure line, or the line to the carb is quite long. So much so it goes down the boat, then comes back up to the tank. I thought this looked pretty ugly, but now I am thinking it was done for some reason due to fuel flow.

My lines are the minimum length they can be. The line from the tank goes down under the engine and back up to the carb. It is at best only 2in long. The pressure line from the tank to the pipe is maybe 10in long.

How long should these lines be?

I am pretty sure I got my tank internally setup right. I used the nylon tubes for it, and bent them such that the pressure line goes up to the bubble on the top of the tank, and the feed line goes to the rear outside corner (assuming right turns only), with a small “V” cut in it, so it can’t be blocked by the walls of the tank.

Eric, I had the same problem with my JAE. So much so, that I was ready to throw the boat on the Freeway that was on the hill above us. I don't know what kind of tank you have, but mine was metal(I made the tank). I've never had problems with my Metal tanks before - and refused to believe that it was the tank. If it is metal/Aluminum or whatever - try a plastic 4 oz. Sullivan to do a test. Larry C. and Dick Dahlhemier pointed me in this direction and it worked. I have also seen where the Nitro in the fuel filter(Skin's-over) the screen. You can check that too.

Actually, I see now that you have some sort of plastic tank. Make sure that the pick-ups are away from the sidewalls of the tank. Pressure and bouncing around causes the tank to flex, and could be cutting-off fuel flow.

 

[Eric Drust]

It is a plastic tank, 4oz. The pickup is right next to the sidewall, so that makes sense it could be a problem.

This pipe came from Zippkits, and I noticed it was full of polishing compound and fibers when I bought it. I cleaned it out as best I could prior to installing it. There is a possibility the nipple is plugged. If this were the case, would it makes sense as to why the engine runs less and less time as the fuel level in the tank decreased?

Right now it won't start, but I only have about a quarter tank of fuel. (Still at work, so I can't add fuel and try it, but that will be the first thing to do when I get home)

 

[Geraghty]

It is a plastic tank, 4oz. The pickup is right next to the sidewall, so that makes sense it could be a problem.

This pipe came from Zippkits, and I noticed it was full of polishing compound and fibers when I bought it. I cleaned it out as best I could prior to installing it. There is a possibility the nipple is plugged. If this were the case, would it makes sense as to why the engine runs less and less time as the fuel level in the tank decreased?

Right now it won't start, but I only have about a quarter tank of fuel. (Still at work, so I can't add fuel and try it, but that will be the first thing to do when I get home)

give me a phone number......

 

[shoboat]

Eric,

You need less propeller like a reduced cup X-438 or a cut down 1440 B/C.

37 mm with no more than 2.73" of cup in the Trailing Edge.

Good Luck Testing,

Mark Sholund

 

[moparbarn]

It is a plastic tank, 4oz. The pickup is right next to the sidewall, so that makes sense it could be a problem.

This pipe came from Zippkits, and I noticed it was full of polishing compound and fibers when I bought it. I cleaned it out as best I could prior to installing it. There is a possibility the nipple is plugged. If this were the case, would it makes sense as to why the engine runs less and less time as the fuel level in the tank decreased?

Right now it won't start, but I only have about a quarter tank of fuel. (Still at work, so I can't add fuel and try it, but that will be the first thing to do when I get home)

you mention the pipe had trash in it & the problem got progressively worse. i think the trash has clogged the fuel filter (if you are running one) or the carb. check ALL of the fuel system, from pressure fitting to carb. a simple test is to put the piston at top dead center (to block the ex. port), & blow in the end of the pipe with the throttle wide open. with fuel in the tank, you should be able to push fuel into the engine through the carb. won't tell you where the fuel system is blocked up, but will tell if it is. and yes, as the fuel gets lower, it does take more to get it to the carb.

 

[Eric Drust]

At this point I am not all that worried about the prop, as stated, the engine will not run on the bench. However, if the prop had anything to do with why my engine won't run, then I certainly want to change it.

Ron, thanks for the offer of phone support. I will have to take you up on that next week. My wife is having our first child tomorrow, and I am pretty busy getting prepared, and panicking as well! When things calm down I will be able to dig into this boat more.

I did check the line out of the tuned pipe, and there was no blockage. I put in a different plug, and tried starting the engine again. No luck starting it with the way it was. I had my wife hold the throttle open all the way on the transmitter, and the engine did start, but I told her to let off as soon as it did. After that I could not get it started again.

This engine has a pull start (I don't own a bump starter yet to try other types of engines), and several times while trying to start it the engine would bind up and the pull start would not retract. If I would turn the flywheel slightly the pull start would retract.

I took the engine out of the boat and tore it down. There is a shaft from the pull start which supports the one way bearing, which itself is supported by a bushing. If I understand this correctly, the shaft rotates in the bushing when I pull the starter cord, and while the engine is running this shaft does not spin in the bushing, the one way bearing spins around it. Well, the busing to shaft fit is pretty sloppy. I am wondering if the one way bearing is loose because of this, and eventually causes the engine to die from the additional friction it creates.

I actually pull stated the engine so much yesterday I wore the skin off one of my fingers. For all I know all this pulling has worn the bushing significantly. That still seems a bit far fetched to me though.

 

[Eric Drust]

It is a plastic tank, 4oz. The pickup is right next to the sidewall, so that makes sense it could be a problem.

This pipe came from Zippkits, and I noticed it was full of polishing compound and fibers when I bought it. I cleaned it out as best I could prior to installing it. There is a possibility the nipple is plugged. If this were the case, would it makes sense as to why the engine runs less and less time as the fuel level in the tank decreased?

Right now it won't start, but I only have about a quarter tank of fuel. (Still at work, so I can't add fuel and try it, but that will be the first thing to do when I get home)

you mention the pipe had trash in it & the problem got progressively worse. i think the trash has clogged the fuel filter (if you are running one) or the carb. check ALL of the fuel system, from pressure fitting to carb. a simple test is to put the piston at top dead center (to block the ex. port), & blow in the end of the pipe with the throttle wide open. with fuel in the tank, you should be able to push fuel into the engine through the carb. won't tell you where the fuel system is blocked up, but will tell if it is. and yes, as the fuel gets lower, it does take more to get it to the carb.

I think you are on to something there. While playing around with the pipe earlier I blew into the line from the pipe and could not get much for fuel flow. I only had it at the idle position though, not full throttle. With the way I had the boat sitting in order to do this, pressure built up in the tank and ended up blowing the fuel back in my mouth. My wife got a good laugh as I ran to bathroom to wash my mouth out. Needless to say, nitro does not taste all that good. I know this stuff is poisonous, but hopefully I will live...

 

[moparbarn]

eric, CONGRATS on the baby coming. and if you were able to make your wife laugh with all the changes she's going thru right now, you're doing something right with the boat :lol: :lol: . it is much harder to force fuel into the engine by blowing in the pressure line than you might think. that resistance builds up pressure in the tank, causing it to swell, so you end up with a mouth full of fuel. try it with the tank in the rtr boat, & use that for a comparison/baseline. btw, if some nitro in the mouth is gonna kill you, i shoulda been dead as a teenager, & lots of times since ........

 

[Jim Mamaril]

One of the guys in our area had the exact problem you are describing,after checking the carb,filter,lines etc. it didn't change, Then we pulled the tank and put mine in BINGO problem solved. I have never used the plastic tubes like you described but I would change them out for some brass tubes and leave the pick up at least 1/4" from any wall or bottom of tank. Another problem that creeps up once in awhile is pulling the fuel away from the pick up in the turns, the JAE's when they up to speed pull a lot of G's thru the turns. I had to make small surge tanks for both of mine and never had the problem again. Rod G. is the one that suggested it to me after hearing about how my boat would surge and then die after going thru a turn,it would always happen after about 3-4 laps when the fuel level dropped. I used 1/2 copper pipe and soldered on some ends and a couple brass tubes,very simple and increases the amount of fuel incase you need to run an extra lap.

 

[TimothyJones]

Hope This Helps

Tim

 

[Eric Drust]

Well, I think I may have narrowed down the issue. Here are some photos of the wearing on the engine backplate from the loose one way bearing support shaft. You can see where the one way bearing has worn a groove into the aluminum back plate. My guess is the damage became progressively worse as I ran the boat, thus causing it to run for less and less time, ultimately not being able to run at all.

The first photos shows the bushing and shaft surfaces, which I have no way of really showing how loose they are, but trust me they fit pretty sloppy. A guy I work with also thought the loose shaft would not allow for proper crankcase pressure which could compound the problems I have had.

For the record, my engine is not nearly as bad looking as those images show it too be. Most of the discoloration you see is an optical illusion from the lighting where I took the photos.

 

[anthony_marquart]

Eric,..

I don't think that would cause the engine not to run at all. I don't run engines with pull starts but I've seen when the one way bearing goes bad you just can't start the motor. Usually it makes it so the pull starter just pulls out, not turning the motor.

It also looks like you are not cleaning and lubing the engine well after running. It you motor has alot of corrosion.

Swap out the tank with any tank and just try it.. Even motors with bad bears,. bad carb o'rings,.. etc,. will start on the bench..

Well, I think I may have narrowed down the issue. Here are some photos of the wearing on the engine backplate from the loose one way bearing support shaft. You can see where the one way bearing has worn a groove into the aluminum back plate. My guess is the damage became progressively worse as I ran the boat, thus causing it to run for less and less time, ultimately not being able to run at all.

The first photos shows the bushing and shaft surfaces, which I have no way of really showing how loose they are, but trust me they fit pretty sloppy. A guy I work with also thought the loose shaft would not allow for proper crankcase pressure which could compound the problems I have had.

For the record, my engine is not nearly as bad looking as those images show it too be. Most of the discoloration you see is an optical illusion from the lighting where I took the photos.

 

[Eric Drust]

The one way bearing is not bad, the shaft which supports it is. Multiple times while trying to turn the engine over to start it, something would bind up and I would pull the boat right off the stand. When this would happen the pull start would not retract. I had to turn the flywheel which was for the most part locked and eventually the bind would come loose then the recoil would quickly snap back into place. If I cannot physically turn over the engine, I see no way in which it could turn itself over while running.

As for the corrosion, it is an optical illusion as I stated. The dark areas are shiny spots which are reflecting the darkness of the room I took the photo in. These parts look very close to new if you were to see them in person.

I have only used this engine three times. It came in the used boat I purchased 2 years back. After the first time I ran the boat (making sure it ran after I had purchased it), I removed the engine and fully disassembled it. I cleaned everything, and then reassembled everything using after run oil to lube all the parts as I put them together. The next time I ran the boat this engine ran like a top (other than some lack of low end responsiveness). When done running I oiled it and then sat it on the shelf. There it sat for 2 years until now.

In all I have run about 1/3rd of a 1 quart bottle of fuel though it.

 

[Eric Drust]

Problem solved! Or so it seems. I have yet to put the boat in the water and see what it does.

After spending a week contemplating this issue, I came up with an idea. Since the one way bearing support shaft fit loose, I needed to find a way to tighten up the fit. What better than aluminum foil!

I cut a small piece of aluminum foil and wrapped it around the shaft, then checked the fit into the bushing. It was MUCH better. I took the foil back off, greased the shaft and the bushing, and then put the foil back on and assembled the pieces. With the grease the fit was even better, almost perfect actually. I put the engine back together, and installed it back into the boat.

On the test bench the engine fired up on the very first pull. It was easier than ever to pull start, leading me to believe this has been an on going problem. It idled just fine, and never quit as I ran the throttle up and down a bit. Now I just need to get the boat in the water and see if it will last.