Looking for help with Idle issue with 2.5 150 XR6

[Bradley T]

Recently installed new pistons, rings and bearings in this 2.5 150 XR6. We have used jay smiths TDC dial gauge and set timing to specs. Problem is it runs away at idle with butterflies on carbs shut. We are now scratching our head's at what's going on. Looking for any advice on a direction to go from here.

p.s Has new trigger and stator also.

[rock]

Welcome to the site. Sounds like you have an air leak somewhere. Motor will not spool up without air.

Rock

[Bradley T]

Would the inside diameter of the bleed hoses affect the amount of air? The original hose seems to be tiny ID replacement hose we used had a larger ID. I am not sure that would affect it but anything seems to be possible.

[Merc 2.5]

I'm guessing run away means hit throttle and it won't come back but keeps raising rpm?

[Bradley T]

No at start up it spools up and will not idle down. Looking for air leaks atm.

[Merc 2.5]

Idle timin if on start up

[Tritontr19]

Upper/lower crank seal, crankcase halves @joint, intake, or larger dia
bleed lines may be pulling air around nipples.

[half fast]

Being a horizontal reed motor if you installed the reed cages to the intake ,then installed that assembly onto the front half it may not be seated to the front half correct. I would try setting the reed cages into the front then set the intake down. Install the screws that hold the intake to the front finger tight ,then the screws from the intake to the reed cages last. hf...