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Stock 2.5 spewing fuel....

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B

beldog41

RC Newbie
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I have an engine stock 2.5(4910). I pulled it out last week to fire up and all was fine for a couple days. Tuned it for the cooler weather we are having now, Upstate NY, and it tore it up for 3-4 days. Now I am having trouble getting it to start? So far I have set carb back to factory settings, then leaned a bit, set idle to .08mm. I have pulled the cooling head and checked compression with my finger, not the best method but at least lets me know if its pulling at all! Not sure where to go from here.

If I crank it over for 5-10 secs it pops a bit but wont start. Then I tip it up on its side and fuel pours our the exhaust but the engine isnt locked up. If I pull the plug to clean out the combustion chamber very little or no fuel comes out? Seems to me like it should be flooded if there is that much fuel coming out the exhaust? Any help would be appreciated.
 
Have you checked your glow plug? Do you use a glow plug ignitor or the blue wire attached to the plug?
 
Yes, forgot to mention that. I checked my old glow plug and it was lighting up pretty good. Put a new one in anyway and it is functioning properly when I hold it against the head. I do still use the ez start for the glow plug. I dont have a glow plug stick.....
 
If your battery is weak on your ez start the glow plug will not ignite charge the battery and see if it starts.
 
nikko508 said:
If your battery is weak on your ez start the glow plug will not ignite charge the battery and see if it starts.
Click to expand...


Right, and this is why I moved over to using the glow plug ignitor. Works better IMO. Have you held the truck upside down and tried to turn over the motor with the ezstart, you should be able to see alot of fuel coming out.
 
Batteries in EZ start at fully charged. Cranks over fast and hard. Have tried turning over to empty head many times. That's the strange part though. It seems like it should be flooded with the amount of fuel that pours out the exhaust when I tip it up, but when I pull the plug and turn the truck over little or no fuel comes out of the head?

I pulled the air filter and cranked it over with my finger on the tailpipe for a second and it was getting plenty of fuel to the carb so I dont think its a back pressure issue.... I'm perplexed though. Its probably something simple I'm over looking.

I'm going to try and get to LHS today and pick up a glow plug ignitor though.
 
So you set your idle gap, right...maybe you set it too small of a gap, and so it closes when trying to prime/start? Did you set it with the transmitter turned on and then check with your brakes applied? Also, use a paper clip to measure the 1.0mm gap.
 
You say that you ran it and it work fine, make sure the blue wire an the glow plug didn't shafe and is now grounding out on the head or an any metal if it is grounding out the plug will not ignite had it happen to me and when I removed the wire to check the plug it worked fine but when I put the wire back on it grounded to the cooling head it took a while before I figured it out so check that and make sure its ok. Next if your running it to lean it will not start and you will get fuel in the pipe I agree with THEANT check your adjustments.
 
When you say you pulled the head, and checked compression, do you mean you checked compression with head off?

If so, check it with the head on. Just pull out the plug, and stick ya finger in the plug hole. You should feel a decent amount of pressure against the end of your finger, to the point that it almost squeezes out past your finger.

But I'm with nikko508... check the plug wire. My Revo did exactly the same thing.
 
Thanks guys. Was something simple as I thought. A combo of your two posts. Blue wire was grounding out on head, had a small cut in wire I hadn't noticed! Also idle gap was a bit small, used the paper clip trick! Actually had to close it a bit after cause it was idling too high. Back to tearing it up!! Just have to get my head cover figured out right, these cold temps are making it hard to get up to heat the engine up... Much appreciated!!
 
Thanks for the tip, have been trying just a sock and I'm having a hard time getting above 200. Ill try some tin foil too!!
 
-11 with windchills at -25 today in MN no outdoor running for me today! but the helis will be getting some indoor flying time!
 

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