mrhydro-inacitve

Hello I am new to this hobby so your assistance would be greatly appreciated. Have new .15 Dynamite motor which is still being broken (now on 4th tank). Needle set very rich as per book (4 turns out), have run boat in water at no more than 25% throttle and using heat cycle method.
Problem I am having is that motor overheats after only 5 min of running and cuts out. Have to let cool down before restarting. When boat is moving can see great flow of water coming out of motor cooling head.
Did not have this overheating problem on previous tanks, seems funny that on 4th tank of break-in motor is now overheating, have not adjusted needle settings, have not changed fuel and there has been no change in air/water temps.
Could problem be that engine needs to be leaned out for performance as stated in book, but I guess that would not be logical as less fuel would mean hotter motor...right!!

By the way motor is being run in a Miss Elam hydro...

ciao

ryan_t888

While helping others I find the most common problem from engines stalling after a short period of time is they start to lean out as they warm up. Although you did say your running it very rich.
I've helped get a Miss Bud going and the problem with it is it had a very lean LSN from the factor completely effecting the tune.
I have also seen where the feed tube in the tank has a hole in it causing the engine to lean out when the fuel level reaches this hole.

How do you know the engine is overheating?

I have car/plane engines that run 220-320F, which is very normal. On my nitro boat engines I can not get them to exceed 180F. I strongly believe ABC engines should run at 220F if possible.

Just a thought
Ryan

mrhydro-inacitve

Hi Ryan, thanks for advise. Fuel tank has screw cap and plastic outlet nipple at bottom, no tube inside like most fuel tanks have. Have leaked tested tank including vent/fuel tubes and no airleaks or pin holes. Do not have a digital meter to tell exact temp but engine is VERY hot to touch by hand. Was never like this on first few tanks during break-in.
Can not see if there is an LSN as carbi barrel view (where throttle arm screwed to barrel) obstructed by boat hull but do not think it has LSN as book says only fitted on Dynamite .32...anyone know if this is correct?

mrhydro-inacitve

Another thought, if I am only running at 25% throttle maximum, would is not be true that HSH setting will have no affect as I am not running anywhere near 100% throttle. If this is the case then LSN must be problem, but if I have no LSN then what to do to solve problem?.....any advise would be appreciated!!
I will go back through book on motor to check for LSN.

saleens7

edit

saleens7

repeat

saleens7

http://www.dynamiterc.com/Products/D...ProdID=DYN6550

according to the description, it has a LSN....

saleens7

the LSN is the little black screw on the top ofd the carb

http://www.dynamiterc.com/Products/D...ProdID=DYN6559

saleens7

edit...i guess....

mrhydro-inacitve

Hello yes you are correct it does have a LSN but I did not get small screw driver for adjusting. Is black screw on top of carb not the idle adjust screw, as LSN is located inside barrel with throttle arm. If engine is running hot now will it not run hotter when more than 25% throttle. Surely I need to richen not lean HSN, otherwise will run hotter...want do you think?.
I read book and yes it says after 2 tanks run more throttle and start leaning HSN but I think in my case emgine will run too hot. I will try pinch method to test if my LSN is correct, or is this waste of time until I get HSN correct. My HSN is at 4 turns but book says 2 1/2 turns for breakin. All this is very strange to me as in theory I am too rich so engine should be very cool!

saleens7

uhhh....edit??

saleens7

edit

ryan_t888

I believe you should take the boat to your pond, start it up and run it. After about 30s-1m run it at WOT. Listen carefully to how the engine sounds. If it is lean it will bog or resist to accelerate and may die. If it is rich it will gurgle/sputter ect. Richen/Lean accordingly

Now that I think about it, the Miss Bud I helped get running had a very similar problem. I continued to richen it to past 4.5 turns and it still ran WAY too lean. I then checked the LSN and it was screwed in too far. After adjusting/richening the LSN I returned the HSN to around 3 turns and all went well for the guy.

I have no way of determining your issue but I believe you may be experiencing the same issue I had.

EDIT: saleen, please edit your posts as you are filling my inbox up

Just a 2nd thought
Ryan

saleens7

wait.....3 turns out from most it will tighten to???

isnt that richer??

thats what is says on my carb....i set it 3 turns and it would richen so much, it would stall when i full throttle it.....then i set it leaner abotu 1/4 a turn from the factory settings and it runs fine......im really confused right now[sm=confused.gif]

atleast thats what the manual says:

http://www.dynamiterc.com/ProdInfo/F...502-manual.pdf

edit:
Ryan, how should i edit them???


edit 2:...ok then ill edit them here......now i just got to rewrite all that info

ryan_t888

It may have been anywhere from 2-3 turns, it was a long time ago. My point is the LSN had an effect on the HSN a it was set extremely lean from the factory. This may be the issue here, or it may not.

I'd suggest to Mr. Hydro to run his boat at WOT and tune to performance and sound from there.


What I mean is instead of replying to yourself, edit your current post to add additional information. For every post on this thread I receive one email. They can add up very quickly.

Ryan

Ron Olson

My Feedback: (1)

You could be either running to too slow so that it isn't getting enough cooling water to the head or you have a blockage somewhere in the cooing system. It doesn't take much, a little algae or other crud can block the waters flow. Check by blowing through the cooling lines to narrow down where the problem might be.

mrhydro-inacitve

Hi Ron have good flow of water from cooling head exit tube on side of hull and tubes are all clear. But I will disassemble cooling head and have a look to be on safe side. Problem definitely oveheat as when motor cool to touch can run boat from idle to full throttle with no problems. But after 5 min run at full throttle, engine becomes hot and starts to lose rpms and eventually cuts out. If you quickly drop throttle back to 25% as soon as you hear rpms start to drop, engine will continue running.
Have no temp probe but if you try to put hand on cooling head it is too hot to touch and testing with water drops, well they bubble and split as soon as in contact with cooling head. I have experience with nitro car engines but have been told that marine engines run way cooler!
Have done fuel line pinch test on engine to check LSN setting. Engine cuts out after 5-6 sec, which according to book is about correct. So maybe problem is with HSH, which is already at 4 turns out.
Any advise is appreciated!

TIA

Wow sounds like its running lean on the high end.

What happens if you turn the HSN counter clockwise another 1/4 turn?

ryan_t888

If you decrease the throttle and the engine runs better, heat is definitely not the issue. As said, it sounds like you are running too lean and starving the engine.

Ryan

mrhydro-inacitve

Hello yes tried turning HSN further counter clockwise (richen) but no diff. Engine is not being starved of fuel until has built up some heat (after approx 5 min running at full throttle). Cooling head has good water flow, so that can not be the problem.
Could it be that it is actually too rich and it is actually bogging down at full throttle rather than running lean. Will try and get actual head temp readings and also try adjusting HSN is opposite direction (lean).
This problem has got me stumped as engine runs great until it builds up some heat. Let it cool down start again and runs fine once more until heat builds up again.
Have an electric pump, might connect it up to cooler head and do some test runs to see if head runs cooler and stops engine cutting out. But I guess I need to first get hold of a digital temp reader.

ryan_t888

Heat doesn't dissapear when the throttle is released. It takes a much LONGER time to dissipate heat energy than a second or two. I believe you have a tuning issue. Richen the needle until you hear stuttering/sputtering/gurgling noises.

If you have excellent water flow through the head I believe it would be impossible to overheat the engine no matter what you do to it.

If an engine is way too rich it will stutter, load up and almost always stall out.

I have my tunnel set up so that it is quite rich for the first minute. I can tell it is too rich from lack of acceleration and some sputtering noises. Once the engine warms up it leans the mixture to an appropriate level.

Ryan

mrhydro-inacitve

Hello ryan, will try richening more but needle is almost ready to fall out if I go too much past 4 turns.

TIA

Is it possible that there may be a piece of sand or dirt or something stuck in the needle valve that could be partially clogging the fuel outlet?

I'm with Ryan on it would be next to impossible to overheat a super rich running motor.

My next guess would be an air leak at the carb or in the fuel tank or lines somewhere so as to partially starve the motor at high rpms when the motor really needs to breath.

mrhydro-inacitve

Have stripped and checked, no blockages. Am on the pond again today so will start from cratch with settings and note engine temps. Will post results on my return.

littlepiston

My Feedback: (12)

ok everything is covered except the fuel tank and holes in the fuel lines check the fuel tanks make sure theres no leaks ,is it a flip top tank or a sealed tank? if its a flip top tank make sure it seals