Hard starting '76 merc

[mikec03]

This is a 20 hp, manual start. It can take 10 to 20 pulls for a cold start. It runs fine once it starts. It's got worse last year. I've taken apart the fuel pump and replaced all parts and I know it's OK. The fuel bulb and line are new.

I understand from reading the posts, that the choke damper has to close tightly to allow the gas to be sucked into the crankcase. But how about the crankcase oil seal, especially the top one. Could it leak air and kill the vacuum?
Or would a leak at the seal be obvious and I would smell gas at the top of the motor?

 

[achris]

Re: Hard starting '76 merc

If it runs well once it's started, then the crank seals are ok... Have you replaced the spark plugs yet? That engine uses NGK BUHW-2. Check you have the right ones, and if you have chumpions, float test them!

Chris...........

 

[mikec03]

Re: Hard starting '76 merc

Thanks for assurance that the seals must be OK. I would sure hate to take the engine apart to get to even the upper one. I now see on another post last March that the carb float adjustment caused a similar problem with a 70's Merc.

Anyone with alternative suggestions for me to check? I think that the spark plugs must be OK but I'll change them anyway.

 

[Chinewalker]

Re: Hard starting '76 merc

That motor has the choke with the pull cable. They are noted for getting out of adjustment. Your motor likes to have FULL choke on cold start, so verify that when you pull the choke knob out that the choke butterfly is closing all the way. If the plastic anchor piece has slipped or moved the choke may not be closing fully...