1989 Evinrude running problems

[mav6759]

What are some causes low compression, could the head gasket cause low compression. the compression 120, 90, and 60.

Mav6759

 

[mav6759]

1989 Evinrude running problems

I checked the compression of the motor, and it was 120,90, 60. What are some causes of low compression. Could this mean that the head gasket is blown. The motor runs great like I said on muffs, and when I put it in gear while on muffs, it stays running, I can take the motor to a higher rpm, but when I put it on the lake, it dies,

Mav6759

 

[Benny1963]

Re: 1989 Evinrude running problems

yes could be head gasket you will normaly see a really clean plug on those low cyl could be scuffing from over heat.try a decarb and see if the numbers come up . but those numbers are low .probaly some damage
pull heads and take a look ,
better luck than i just trashed two cyls by over heat and had good comp numbers but had piston damage
bennyb

 

[wavrider]

Re: 1989 Evinrude running problems

Need to post what hp engine you have, model helps also in most cases.

The engine runs on muffs at the yard, there is no back pressue so it will run, start easier. the exhaust is through the foot and when at the lake it has back pressure, also in a barrel it will have pressure as the foot is submerged.

The compressions number you have are way off. all cylinders should read within 10% of each other.

Reccomend get a manual, OEM prefered, Seloc is ok but OEM is the best for details.

If you can pull the head and take a look at the gasket and try to see why your compression is so off. You have a diffeence of 60 lbs between #1 and #3, that is one reason why it will not run at the lake. Let us know what you find out on the head gasket.

There are many reason for low compression, wrong mixture, lean or dirty carbs cause cylinder to run lean, blown or damaged head gasket, over heating, worn or damaged rings, warped or out of round cylinder, list goes on.

 

[rodbolt]

Re: 1989 Evinrude running problems

yep, its head pulling time, if your lucky is a blown head gasket. if not stand by.
if the head gasket is blown have it carefully checked for warpage and find/correct the overheat that caused it.
if this is a four stroke a leak down shold be done before tear down.

 

[JB]

Re: 1989 Evinrude running problems

PLEASE, Mav! Tell us what engine you are asking about.

 

[JB]

Re: 1989 Evinrude running problems

Double post