Engine Trouble Engine wont start? TROUBLESHOOTING GUIDE

gary55

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Like crassius is saying. If it repeatedly speeds up and slows down at wot with no change in throttle position There is a good chance the motor mounts are not tight enough to keep the engine from vibrating and foaming out the fuel bowl.
 


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When the engine speeds up at WOT due to frothing/ foaming caused by vibration, it's a lean condition. The same thing happens when your fuel level in the float bowl is low. (Forgot to turn pet cock on) or running out of gas.
Also if the float is not correct or lack of fuel flow from tank to carb (dirty fuel filter), Will cause the carb bowl to be low enough to suck air with the fuel and create a lean condition.
 

gary55

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A to lean condition such as a intake or seal leak often causes the engine to speed up. The foaming of the fuel in the bowl caused on a engine when it reaches it's harmonic point and has loose mounts does just the opposite. The engine slows down then when it drops below the harmonic point the vibrations cease, the fuel settles down and feeds properly, it then speeds back up. It is not speeding up cause it's lean. It's speeding up cause it's running correctly. This will be a repeating cycle with no change in throttle position.
 

crassius

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if you mean the head studs, then you have a bad (or maybe just loose) gasket

spark plug or muffler loose could sometimes blow air up there
 
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I found the leak theres some huge casting flaws in the spark plug area theres some slag that goes from the tread all the way threw to the side about a half inch of travel im going to jb and see what happens after i burn of impurities on stove
 

Eric Hall

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hope its alright i'm posting in an older thread, but just have a few questions...


okay, so i shocked myself testing the spark plug (idiot), so i know thats working.

the clutch works great, i can feel and hear it turning the piston when i try to start the engine, so thats not the problem either.

what i have come to think is that it is a carb or throttle problem


i get the engine to turn over, hear it start firing, but as soon as i pull in the clutch it cuts out.


things i have already tried:
the fuel line is 'on' at both the tank and the carb, i used the tickler button and could see gas flow down the line (an air bubble anyhow).

PS, glad to be joining the MB community :D
I am having the exact same problem. Have you found a solution yet ????
 

crassius

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there is a thread here with all the steps to get a motor to start - if you have spark, then next check is to see if spark plug is wet
 
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My engine seems extremely flooded with the muffler off and the plug out and the clutch locked engaged you can hear it sounds like the engine is full of gas how do you fix that I'm wondering if my petcock is broken it seems the fuel filter stays full no matter on or off I tried haluing ass and it shoots out of the exhaust port but never seems to really make a difference should I drain my tank
 
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