What next 15 johnson

[green_head_getter]

Hey guys 15R78B
motor wasnt running good at idle, starts running rough and when i idle lower it stalls and dies. Hard to start. I thought it was the carb. Cleaned it and put a kit in it twice in 5 days. I assure you its spotless. I thought it might be fuel related so i mixed fresh gas, installed new hose clamps on all fuel lines and put a brand new fuel pump in. Still hard to start. I checked my float in carb and it is positioned good. I did the air blow test. New plugs and decarbed. The thing still doesnt like to idle low. What could it be?

 

[green_head_getter]

Re: What next 15 johnson

I want this baby to start in 2 pulls like it should. I havent ran a compression test yet. Could that make it not want to idle

 

[green_head_getter]

Re: What next 15 johnson

Also when starting it wont try unless its at wot
and choked, it will barely fire, push in choke, then about 3-5 pulls witj wot and itll fire off and start running i thot choke was for low gas not
too much gas

 

[Rick.]

Re: What next 15 johnson

Have you done a linc and sync after replacing the carb.? A compression check would be a good idea. The choke richens the fuel to air mix as in more fuel less air. Best of luck. Rick.

 

[green_head_getter]

Re: What next 15 johnson

Link and sync? Explain please, i know my timing is off at y hamdle however i was just going to remark my handle and call it good. With my cowlin off i can watch and my motor will die out 3/4" before my roller gets back down to the arrow on my timing plate, it should idle at that arrow right?

 

[AlTn]

Re: What next 15 johnson

yes..your motor should idle at that mark...and even with the roller off the timing cam completely...it should idle.... Cofe explained the link and sync procedure in an earlier post....yes...a compression test is in order as is a spark test...7/16" air gap jump with a spark checker...what else can cause poor or no idle?...air leaks from the upper main or lower main seals or both...air leaks between the case halves...reed valves getting funky...engine worn to the degree that the lower piston skirt to cylinder clearances are so loose you're losing "sucking power" on the vacumn side...in short,a litany of things you can only deal with one at a time...w'o a complete rebuild ,your motor may never be a "1 or 2 pull wonder"..even with a rebuild, it may never be that...link an sync...compression...spark...deal with those first