Tuning a RTR .15 Engine

[Eric Drust]

I removed the .18 in my RTR boat to put in a used dynamite .15 I had. This was partially to make sure the .15 worked, and second to practice tuning a glow engine.

I started by putting the needle settings at the factory recommended settings. Like this the engine would not idle unless the glow ignitier was always on the plug. The low speed needle seemed way too far out so I leaned it up a bit, and eventually got the engine idling without the glow igniter.

Now where I am at with it the engine dies when I give it some throttle. I can't run the boat in the water at this point, as it will just die at idle when the water loads the prop, and I can't give it some throttle to launch the boat and keep it going.

What should I adjust now?

Also, I noticed when the engine dies and I tip the boat back a lot of fuel/oil mixture drains out of the pipe. I never remember this happening with the .18 engine in there.

 

[misshydro]

I removed the .18 in my RTR boat to put in a used dynamite .15 I had. This was partially to make sure the .15 worked, and second to practice tuning a glow engine.

I started by putting the needle settings at the factory recommended settings. Like this the engine would not idle unless the glow ignitier was always on the plug. The low speed needle seemed way too far out so I leaned it up a bit, and eventually got the engine idling without the glow igniter.

Now where I am at with it the engine dies when I give it some throttle. I can't run the boat in the water at this point, as it will just die at idle when the water loads the prop, and I can't give it some throttle to launch the boat and keep it going.

What should I adjust now?

Also, I noticed when the engine dies and I tip the boat back a lot of fuel/oil mixture drains out of the pipe. I never remember this happening with the .18 engine in there.

First you shouldve left the.18 in it. better power then that.15. Two you need to first turn your hight speed screw away the way in. Then turn the screw back out about 2 1/2-3. Then start form there. Also put in a new glow plug too,should like its bad. You last question sound like its still running on the lean side too.

 

[Eric Drust]

I realize the .15 is less power than the .18, but I plan to get rid of this boat and use the money for another project the .18 will go in. So, start with the high speed needle almost 3 turns out from the most in it can go...

will do and report back.

 

[Eric Drust]

Well, as it turns out, just under 3 turns is where I had the high speed needle set at.

So now which direction should I head?

 

[robertpickard]

Start at 3 full turns out if it is still giving you trouble open the low end some. How far are you getting before it quits? also check your bearings they might be bad.Iwould check the bearings first before doing anything else.

 

[Eric Drust]

At the moment the engine will idle just fine without the glow igniter on it. As soon as I give it any throttle it dies.

 

[misshydro]

At the moment the engine will idle just fine without the glow igniter on it. As soon as I give it any throttle it dies.

I that this happend to me on my JAE.12 rigger. Two thing this can be. One you could still be alittle to rich. Two can be a bad glow plug. If thats a .15 dynamite/dynajunker. Try to turn the needle to 2 1/2. Think mine ran on 2- 2 1/2 turn open.

 

[Bob Morton]

What prop are you using? Try a smaller prop .

 

[Grimracer]

Eric,

Use fresh "BOAT" fuel..

Turn the low speed needle all the way so its flush with the barrel face or even further out then that.. just make sure its out of the way..

Set the High Speed Needle at 3 turns out

Adjust the carb so the barrel is 1/4 open when you are starting it.

Use a OD-9 plug or med heat range plug..

Start at that and let us know what happens

Grim

 

[Eric Drust]

I have a bunch of OS #8 plugs, and my fuel is O'Donnell 30% boat. Any concerns with either of these, the combination works great with my functioning engine.

 

[misshydro]

I have a bunch of OS #8 plugs, and my fuel is O'Donnell 30% boat. Any concerns with either of these, the combination works great with my functioning engine.

Thats one of your proublems. If your using O.S#8 on 30% is to hot of a plug. anything 30+ needs to run on a cooler/cool plug. You need to try O.S R5 or A5. if not O.S. Get ODonalds blue or MC9's.

 

[Ron Olson]

Usually after removing the ignitor and it dying indicates a too-lean condition. How's the plug looking?

 

[Grimracer]

Truth is the hotter the plug the better the motor will run under light loads..(on the shore and what not).. but in the water it "might" be a different story.

Its important to remember if it idles clean and crisp on shore its likely lean on the water.

Set up right a good marine engine will have a either smoky fast or rich high burble at idle.. Its really a high idle as best.

IF you’re marine engine sits at idle and ticks em off like a RC car engine its just not going to run on the water… its likely to lean.

Grim

 

[Eric Drust]

Well, you guys have established one thing, I have a lot to learn!

The plug looks like new. Shiny filament.

I will mess around with it on the water this weekend and see that I can come up with. If I don't get it going right, no big deal, it is not critical this engine works, I just wanted to find out if it did.

 

[misshydro]

Truth is the hotter the plug the better the motor will run under light loads..(on the shore and what not).. but in the water it "might" be a different story.

Its important to remember if it idles clean and crisp on shore its likely lean on the water.

Set up right a good marine engine will have a either smoky fast or rich high burble at idle.. Its really a high idle as best.

IF you’re marine engine sits at idle and ticks em off like a RC car engine its just not going to run on the water… its likely to lean.

Grim

I'd leard this trick from the girl pressent form madison IN boat club. put your hand back at the exaust. if its spitting oil pretty decently on your hand its close. Thats two things I do the burp the engine,if it bogs alittle and then clears out and the oil output the tune pipe.

 

[gooycheese]

sounds like grim has some real good advice

The bearings are another thing, if you are 100% sure they are good then no problem. I am learning your boat starts doing anything funny like dieing running lean ..... acting antyhing different burning plugs.... check the bearings now before ya break a rod or race. Ya may need a helper to keep the boat running, a lean boat alot of times wont launch but a rich boat will run and putter around .... if too rich it wont run either but you sound lean. ohhh are all the lines good(pressure and fuel) and no blockage in the needle?

 

[moparbarn]

I have a bunch of OS #8 plugs, and my fuel is O'Donnell 30% boat. Any concerns with either of these, the combination works great with my functioning engine.

in my 'fun' boats (not race boats), with k&b .21's on 30% the OS8 is my favorite plug. have you taken the carb apart & cleaned it? what bob morton suggested, also, smaller prop.