Signs of bad compression

[BASSNSNOW]

my 115 merc runs fine top end @ just under 60 mph, but it stalls when going from neutral to gear and it has a rough low rpm i was just wondering if this is one of the signs of poor compression

 

[Fouled Plug]

Re: Signs of bad compression

Depending on the hull, if you're going close to 60 I think the compression may be OK. Could be in need of new plugs and a tune up. Start with the basics, and get a compression gauge. Cheap troubleshooter, and very handy to have around.

 

[my new fishmaster]

Re: Signs of bad compression

Its the fuel delivery check out your fuel pump replace with a rebuild kit for $12. New fuel filter and could be the bulb pumper thingy.

 

[kev_79]

Re: Signs of bad compression

What year model? If it's a 4 cylinder, it is a 2+2. Check idle air screws on top two carbs, right side looking down the throats. Adjust them to 1 1/2 turns out from set. Also, a can of power tune couldn't hurt. Good Luck

 

[12Footer]

Re: Signs of bad compression

And if it is the V6,check the low speed winding of the stator.

 

[kev_79]

Re: Signs of bad compression

Also, I was wondering, what kind of boat and prop you are running. That is a pretty good top speed. I am running a 115 on a fairly light bayliner 18' and I can only get close to 45 with a 21 pitch prop. I am trying to figure out if my prop is slipping a little.

 

[OBMD]

Re: Signs of bad compression

How about doing an actual compression test? Do one every year as a base line for future reference.

 

[BASSNSNOW]

Re: Signs of bad compression

got my compression checked and it was good all 4 cylinders were at about 12o. so i guessing it has to be the fuel delivery system also it had a good strong spark is this a good assumption

 

[hondon]

Re: Signs of bad compression

What altitude are you running at?

 

[BASSNSNOW]

Re: Signs of bad compression

i dunno i live in san francisco