merc 500 hard cold start

[maineiac5586]

I Have A 76 Merc 500, Rebuilt The Carbs, Flat Levels Set Perfectly, Issue Is When I Have To Start It Cold It Cranks For A Second And Coughs, Then I Have To Keep Cranking Starter, It Takes Many Times Of This Before I Can Get It To Fire Up And Idle. Choke Works Fine, Primer Bulb Gets Hard. Once Warmed Up Works Fine. It Seems Like Starter Doesnt Want To Keep Turning Motor Long Enough For It To Start. As Soon As It Senses The Motor Is Firing, Starter Kicks Off. It Seems Like It Kicks Off Too Soon And Needs To Continue Spinning The Motor To Get A Good Start. Does This Make Sense And Does Anybody Know A Solution.

 

[coolguy147]

Re: merc 500 hard cold start

check compressoin and spark

 

[maineiac5586]

Re: merc 500 hard cold start

compression and spark good, it is like something is telling starter to stop spinning as soon as motor coughs to fire up, it needs to spin longer to start. starts fine when warmed i believe because you only have to bump the starter to get it to start. also when it finally fires up when cold it seems to run for about a few seconds at a very slow speed even though i have throttle all the way down (gears disengaged) and then all the sudden it revs up out of control and i have to return throttle to neutral. from this point on runs fine and idles fine, doesnt die when put into gear. this only happen on 1st start after launching from trailer. help please

 

[coolguy147]

Re: merc 500 hard cold start

is there a fast idle lever?

 

[maineiac5586]

Re: merc 500 hard cold start

on my controls i pull the throttle to the left and the i can rev engine up with the engine not being in gear. i have a ultraflex top mount control on a center console. the range is idle to wot

 

[maineiac5586]

Re: merc 500 hard cold start

anyone know how to diagnose this?????

 

[coolguy147]

Re: merc 500 hard cold start

i would make sure u dont have a intermient spark on and off like so. also make sure ur carbs r clean.

does this model have a fixed high speed jet im unsure

 

[maineiac5586]

Re: merc 500 hard cold start

carbs are spotless, spark good, yes has fixed jet, could starter motor being worn cause this?