1983 Merc 25 Kicking on start

[mcdgary]

Motor cranks easily before running. After I run at optimum speed (say 3-4 miles) on the water, stop and then restart it kicks real hard. Letting it set for a while, it cranks normally without kicking. Running it at home in a water tank I can go a long time, stop and it retarts normally, does not kick. Help!

 

[north40]

Re: 1983 Merc 25 Kicking on start

Could be preignition caused by carbon buildup and or timing. Do a decarb first and see if you see difference.

 

[mcdgary]

Re: 1983 Merc 25 Kicking on start

I forgot to put Merc Serial # -- 6185448, and I want to add 2 questions: Does this motor have a thermostat? The telltale looks as if it comes out of the cylinder head, which means this water output has circulated completely thru the cooling system, right?

 

[north40]

Re: 1983 Merc 25 Kicking on start

No thermostat. Water circulates thru head.

 

[mcdgary]

Re: 1983 Merc 25 Kicking on start

Placed motor in tank of water. (First) Cranked motor (went to fast idle), sprayed (liberally) Sea Foam into carb (several successive shots), finally sprayed Sea Foam into carb until motor stopped. Removed the two plugs and sprayed a generous amount of Sea Foam into each cylinder and let motor set for an hour+. Now when I attempted to crank motor I got a good KICK. P.S. If timing is off why was motor easily cranked at first???