3cyl runs on 2 when cold help prevent a blown piston !!!

[RaScLeS]

when my 1979-80 70hp starts up its running on 2 cylinder and revs up slow (which is how i can tell) I have to let it warm up for a couple minutes then i leave the dock and put it in gear and go

sometimes it wont pick up the third and just be slow, to remedy that i had to rev it in neutral and then try again.

normally once I put it in gear and go past half it kicks in and goes fine until you let it sit a while. id rather this not happen but i dont know what causes this problem. it has a brand new trigger. I have a spare powerpack to try aswell but i dont think thats it. let me know as id like to not have cyl 1 blow out next time it "kicks" in

 

[RaScLeS]

Re: 3cyl runs on 2 when cold help prevent a blown piston !!!

COME ON, anyone ? i dont want this thread to just die like all my other ones, could the pack be causing a cold misfire of cyl 1 ? cause its doing nothing when cold. once i hammer it i can get it going and it runs mint. i want this engine at its peak for its year please help !

 

[Fuzzytbay]

Re: 3cyl runs on 2 when cold help prevent a blown piston !!!

It could be the pack, it could be the carb, it could be the trigger, it could be timing, it could be the spark plug! IF this has happend, over and over, then your plug is fouled, and needs to be changed. Sounds to me like thats the case. Try being proactive, if you have a problem, discribe it, and also mention what you have done to try and fix it,or think might fix it. A fouled plug will fire and burn at high temps, not low ones. Thats why fouled plugs need to be changed.

 

[RaScLeS]

Re: 3cyl runs on 2 when cold help prevent a blown piston !!!

new plugs new trigger new coils 2 packs have been tried good gas and oil good compression timing and carbs were done. i dont know what it is, i cleaned the top plug after it first happend, seemed to help a bit. I just dont want the piston to blow out the wall when it kicks in

 

[sschefer]

Re: 3cyl runs on 2 when cold help prevent a blown piston !!!

new plugs new trigger new coils 2 packs have been tried good gas and oil good compression timing and carbs were done. i dont know what it is, i cleaned the top plug after it first happend, seemed to help a bit. I just dont want the piston to blow out the wall when it kicks in

O.K. since you've checked all the obvious pull the airbox cover off of it and tell us if the carbs are spitting excessive fuel at idle. Also, what is the compression on each cylinder.

 

[Fuzzytbay]

Re: 3cyl runs on 2 when cold help prevent a blown piston !!!

Something is not "done right". Assuming, timing and carbs are synced, then I'd vote on the carbs, check the float. The problem, I guess is when starting the number 1 cylinder floods out the plug. Only reason's I can think of are floats in the carb, carb is not in sync, or the reeds are damaged. Who rebuilt the carbs? Also who did the trigger?

 

[flasher]

Re: 3cyl runs on 2 when cold help prevent a blown piston !!!

if it was me,i would first determine if it was a fuel or an electrical problem.if it was running on two cyl ,i would let it run for a couple of minutes and the pull the plug out and see if has fuel on it.or i would run it on the two cyl and see if it has a spark coming out the wire on the cyl thats not firing.hope that helps

 

[Fuzzytbay]

Re: 3cyl runs on 2 when cold help prevent a blown piston !!!

bump so others may have a clue as to whats going on in his new thread

 

[RaScLeS]

Re: 3cyl runs on 2 when cold help prevent a blown piston !!!

well the motor ran amazing once on three, i took a passenger out in my boat, hit wot once before getting to the dock bog bog bog no power again, new trigger professionally installed has failed or something else. what a sad case.