Jae12 from yesterday first run

[Davidkrienke]

I was able to get pauls boat running yesterday I bought from him. I tried a few props . This is with a back cut and detounged x438 prop. It was doing the hop hop I am unsure what to do to fix it? Was it just the rough water ? I tried a 1440 mark prepared and 30 percent fuel couldn't pull it . also tried a x437 and a y536 it was good but no rpm. All were pretty jumpy Any prop help on this little guy would be appreciated.

 

[Davidkrienke]

Also It was hard to get enough heat into it . I took and taped over the fins but it still couldn't get hot to burn more fuel. If I went too lean it would just bog and die once I think the temp was coming up. It had a #6 plug in the lt12 nova engine. Pipe is at 6 1/2 inches .Would a hotter plug help?

 

[ChrisCapaldi]

Hi Dave, You may want to take a little angle out of the strut to try and flatten the ride. I have my stuffing tube all the way down on the ski. This will put more prop in the water so I have to run the pipe (also a Texan) longer...7.25" to 7.5". My boat finds the Mark S 1440 Lynx cut the easiest to run.
Hope this helps.
Chris

 

[Davidkrienke]

Hi Dave, You may want to take a little angle out of the strut to try and flatten the ride. I have my stuffing tube all the way down on the ski. This will put more prop in the water so I have to run the pipe (also a Texan) longer...7.25" to 7.5". My boat finds the Mark S 1440 Lynx cut the easiest to run.
Hope this helps.
Chris

Thanks for the reply Chris. At first we did have the strut touching the ski but the strut came loose and we had to remove it and tighten it then decided to lift it up some. I will drop it back down and give the 1440 a go again with longer pipe. I was just trying to get that little engine to scream to hit its peak power curve . We had the pipe at 7 inches earlier in the day and I saw a rpm increase when I pushed it shorter so I left it there for the x438 . I wondered if I could cup the prop on the outside edge to get it to not bounce in the corners but hate to mess a prop up bending on the edge like a caveman. I might try to round the corners of the trailing edge tips on my 438 like marks prop too . Wish I was rich and had a bunch of the same prop to really bend around on them.

 

[BrianNeumann]

I’m at work and only glanced at your post, hopefully not repeating too much. I noticed right away what Chris had already suggested. The strut is too high and should be right against the ski, that is probably causing the hopping issue. I also have no issue running the 1440 that Mark preps for a JAE 12, great prop and always launches. I don’t think you need to mess with it. Is the engine broken in? It takes about a gallon of fuel while running rich, and keeping the temp up to roughly 200 degrees for it to break in. You will be able to turn it over by hand (still difficult) it will wake up and starting singing once it’s truly broken in. I would remove the heat sink and run with just the head button if water & air temps are cool/cold. Adding a cowl to mine was a huge help getting the engine to build and keep heat. Began to run consistently, & helped keeping a rich needle to burn all that fuel and make rpm’s. I also will run mine on shore for a minute or more, helps warm up the engine before tossing it in, especially when it’s 60 degrees or less outside. A Nova 5 or 6 plug works great. Also 60% nitro if you have some. Head clearance set at .006-.008” is a must. I’ve never ran the Texan pipe, so follow Chris’s suggestions on pipe length. Good luck, I hope you get yours running well next trip!
Brian

 

[Davidkrienke]

I’m at work and only glanced at your post, hopefully not repeating too much. I noticed right away what Chris had already suggested. The strut is too high and should be right against the ski, that is probably causing the hopping issue. I also have no issue running the 1440 that Mark preps for a JAE 12, great prop and always launches. I don’t think you need to mess with it. Is the engine broken in? It takes about a gallon of fuel while running rich, and keeping the temp up to roughly 200 degrees for it to break in. You will be able to turn it over by hand (still difficult) it will wake up and starting singing once it’s truly broken in. I would remove the heat sink and run with just the head button if water & air temps are cool/cold. Adding a cowl to mine was a huge help getting the engine to build and keep heat. Began to run consistently, & helped keeping a rich needle to burn all that fuel and make rpm’s. I also will run mine on shore for a minute or more, helps warm up the engine before tossing it in, especially when it’s 60 degrees or less outside. A Nova 5 or 6 plug works great. Also 60% nitro if you have some. Head clearance set at .006-.008” is a must. I’ve never ran the Texan pipe, so follow Chris’s suggestions on pipe length. Good luck, I hope you get yours running well next trip!
Brian

Great thanks brian for the tips as well. I will try all you mentioned. I am only using 30 percent but I am sure the fins off will help a bunch if I can remove them. Its a head someone put on there from a air cooled turbo motor . its broken in and has a great fit so I just need to keep messing with it. It just needs to get that temp up so I can feed it more fuel and I will make more power. I will drop that strut back to the floor too and see if that helps with the hop.

 

[Davidkrienke]

I checked squish and it needed the shim removed that was 11 thou. And I was able to use just the button . I think this is going to be the ticket. I still may need a cowl to get it up to temp so maybe a pepsi can around it is next . It will have gobs more power at 6 thou where its at now. Dropped the strut too. cmon warm weather.... Glad you chimed in also. great great great.

 

[Glenn Quarles]

Yeah the head clearance is the deal! I ran my .12’s at .004”. You should be able to run that pipe as short as you can get it. You never mentioned the weight of the boat, it’s important with these little guys. For a heat racing boat 2 lbs rtr was always good for me. At that point you be be adding cup to the 1440 or going to a bigger prop.

 

[Davidkrienke]

Its 36 oz with no fuel. I have the header just sticking in the pipe a inch or so should i cut it off so it doesn't go in the pipe or is it ok this way ?I also wanted to ask did you thin the rudder as much as possible or leave it be?.

 

[Glenn Quarles]

Its 36 oz with no fuel. I have the header just sticking in the pipe a inch or so should i cut it off so it doesn't go in the pipe or is it ok this way ?I also wanted to ask did you thin the rudder as much as possible or leave it be?.

Ok so the weight is ok. If there are any areas where you can shave off a bit you might try that at some point, but at 2.25 lbs you are ok. Yes I would cut the header off so it only sticks inside the pipe about 1/4” or so. I don’t know about that rudder, but the general rule on these 12 boats is to make every effort to minimize drag. I use knife blade rudders on all my boats now, but have used the Speedmaster mini rudders with good success in the past.
The biggest thing you can do to help the performance is reducing the head clearance (and head volume, but that’s for another discussion).

GQ

 

[SayMikey]

That glow plug looks like a rossi, id get a k/b or car plug. Make sure all the edges are sharp and also make sure the sponson bottoms are flat.

 

[Davidkrienke]

That glow plug looks like a rossi, id get a k/b or car plug. Make sure all the edges are sharp and also make sure the sponson bottoms are flat.

I need to still check the bottom for flatness they look pretty sharp . I noticed a 6 on the plug and it was threaded all the way down so maybe it is a Rossi. Can a os plug seal in a rossi head? .I did wonder about running a hot plug like a 3 or 4 in it. just didn't know only running 30 percent nitro if that would cause it to detonate. I really appreciate everyone helping me with this. Just feel so humbled having so many great minds on here to help . Cant wait to get it back out and run it .

 

[SayMikey]

OS works fine, The more nitro you pour to it the better off you are. I run at least 60% IN SMALL MOTORS

 

[Davidkrienke]

I would love to run higher nitro but here is Kansas City it is impossible to find over 30 percent. I just know when I get a hold of some 60 or 65 percent I will want to run it in everything and its close to 70 a gallon on ebay. I know this little guy has a 4 oz tank and doesn't burn much but the temptation is definitely there once i get some to run it in all my .21 engines too.

 

[Glenn Quarles]

David, where do you run in KC?

check with John Otto at Technology fuel to see what his price is on 60%. It’s great stuff! Also check to see if your local hobby shop will get you some VP Powermaster 60% for a good price.

GQ

 

[Davidkrienke]

David, where do you run in KC?

check with John Otto at Technology fuel to see what his price is on 60%. It’s great stuff! Also check to see if your local hobby shop will get you some VP Powermaster 60% for a good price.

GQ

I will check with Hobby town again but he was not bringing in much else than car fuel that I add 6 oz kl205 too for 40 a gal because of hazmat charges he said. I run at my local lake here called smithville lake with my son.

 

[Glenn Quarles]

My son lives up in Gladstone and we have been to that lake several times. We’ll have to get together next time I come up there!

Check withJohn Otto on the fuel!

GQ

 

[Davidkrienke]

My son lives up in Gladstone and we have been to that lake several times. We’ll have to get together next time I come up there!

Check withJohn Otto on the fuel!

GQ

Small world my family all lives in gladstone as well. Anytime your welcome for a boat ride and some running of boats

 

[SayMikey]

Our Hobby Town has 60% for $54.95 a gallon

 

[BrianNeumann]

Glenn knows a thing or 2 about 12 riggers, and the Texan Pipe, so definitely follow all his advice! John Otto 60% Fuel is what I run in my nova 12 as well, and it’s great fuel. His prices are very reasonable including shipping cost considering the hazmat fees and that he is a fellow boaters mixing small batches of fuel. I do not know if this is actually true or not, I either read or heard someone say that OS (turbo) plugs use a slightly different cone angle design compared to a Nova plug & other Italian made plugs. switching from a Nova or Rossi plug to an OS plug could create a a sealing issue. Since The button has formed it’s sealing surface from a Nova plug cone angle instead of an OS cone angle if that makes sense? Again I cannot verify if this is true, referring to Turbo glow plugs only. Glad you rechecked the clearance and lowered it. My JAE 12 currently weighs 2Lbs 3oz w/o fuel for reference. Keep us posted.
Brian