Ive been racking my brain trying to figure out what is wrong with this thing. I pulled the motor off to check compression and its good. I sealed the backplate and carb. Checked all the fuel lines. New glow plug, fresh fuel. Still the thing wont stay running. I got it to fire a couple times and it would only stay running if i hed the throttle wide open. Ive leaned it out and richened it up. Tried the carb slide in many different positions. Im at a loss, my jato 3.3 runs perfectly. Anyone have any imput or ideas? Btw the ez start batt was fully charged also.
When it's running withe the throttle held wide open is it running wide open, high rpm, or is it just barely limping along? A stupid ? but have you verifid that the slide is opening fully and you are getting fuel to the carb.? Have you done a leak test? How old is the engine? Have you pulled the flywheel and checked the bearing dust seal/shield? Have you taken the carb apart and cleaned it? For my information how did you check compression? Just a few thoughts...
Its pretty high rpm but not near how wot should be. I did check the slide, it opens and closes as it should. To check compression i relied on a good ole youtube video, first by tuning to motor over and listen for the "pop" . Then it showed how to take out the piston and sleeve to make sure the sleeve wasnt worn ( piston will stop before it gets to the top of the sleeve). I also blew the carb out, basically just took the screws out.It def has me puzzled at the moment
And i did hold my finger over the exhaust to prime it. Seemed like it primed a little slow.
Last edited by Double G; 09-19-2013 at 09:18 PM. Reason: merge
That could be a hint. I've been having trouble lately with ms exhaust seal leaking. The one between the header and the pipe. You might also check your fuel line and tank for air/pressure leaks. If you have an inline fuel filter make sure it's clean and sealed. I wonder too if your in tank filter may be clogged. Never heard of this but who knows. It has to be something relatively simple after all these engines are pretty straight forward. If you have fuel reaching the engine, air reaching the engine, sufficient compression, and a heat source, it pretty much has to run. when I have a problem I can't diagnose I find it helpful to just leave it for awhile and come back to it later when you're not as frustrated.
Is there supposed to be an actual gasket between the block and header flange? There is just a thin oring between mine. I also noticed the coupling is loose where its attached to the pipe. Guess ill grab some new zip ties tomorrow
Yes, there's just an o-ring between the block and header. It's more than good enough, as long as nothing is bent or broken. A loose or broken coupler will definitely stop it from getting enough fuel.
it also could be you have a teeny clog that wont come out by blowing air through it in the hsn that all you have to do is screw the hsn in all the way and then unscrew it four turns and then try that and if it works re tune. hope this helps!!
I had the same issue. Mine was a small crack in the header just outside of the bracket that held it to the motor. I didn't figure it out until it broke off completely...