40 hp merc 2 cyl

[wildthingn]

will scored cyl's cause hi compression

 

[jimmbo]

Re: 40 hp merc 2 cyl

no, but they can cause low and no compression

 

[wildthingn]

Re: 40 hp merc 2 cyl

ok ,I talked to a boat macanic and that is what he said, my problem is the motor is hard to turn over, the starter is good, and I checked the float and unhooked the hose from the fuel pump, and removed the plugs and turned it over several times with a pull rope, put plugs in and still very hard to turn over what could be the problem, do these engines have a reed valve..

 

[jimmbo]

Re: 40 hp merc 2 cyl

Is the engine hard to turn over when the plugs are out? Yes it does have reed valves.

 

[wildthingn]

Re: 40 hp merc 2 cyl

turns over easy with plugs out.

 

[jimmbo]

Re: 40 hp merc 2 cyl

If an engine has higher than normal compression then there might be an unsual amount of carbon in the combustion chamber or on the piston dome. Try using some SeaFoam or one of the engine cleaners. It could be normal. Have you done a compression check yet? If yes, what are the numbers?

 

[wildthingn]

Re: 40 hp merc 2 cyl

compression on one was in the 90's and the other about the same, if i got a good reading,, i will try another reading with a different tester as soon as i get one...

 

[jarand82]

Re: 40 hp merc 2 cyl

I dont know what year ur motor is but my 78 40 hp merc has about 120 psi
on both cyl. and it rolls over fine. might want to check ur battery. did u have the starter tested? some times they can go bad but still spin, just wont have enough balls to turn motor.

 

[cannonford57]

Re: 40 hp merc 2 cyl

good call jarand, starter has 2 sets of brushes probably has a brush stuck or burnt.

 

[wildthingn]

Re: 40 hp merc 2 cyl

the engine is a 1982, my problem is even if the starter was bad it has a optional
rope to start the engine, and when you try to pull it with the rope you cant,the starter bushing are bad and im in the process of replacing them,i just want to know what could cause it to pull so hard, last year the battery went bad when we were on a lake and we started it with a rope several times, but the last time it was used the engine died and could not get it started with the rope,with the plugs out it pulls over easy, but with them in you can't turn it over, what might cause that..

 

[jarand82]

Re: 40 hp merc 2 cyl

Mine is very hard to start with the rope to. I don't know what would cause it.