low compression in #3 and possibly #4 cylinder

[nightimefishn]

Can electrical issues cause incorrect compression results? I don't think so but I am really not sure.

 

[emckelvy]

Re: low compression in #3 and possibly #4 cylinder

No Way! Compression is strictly a function of the sealing ability of the pistons & piston rings to the cylinder walls, to compress the fuel/air mix as per the engine's design characteristics (for example, as related to bore/stroke and compression ratio).

Electrical problems can lead to engine problems that can lead to poor compression, but if your starter is cranking over at normal speeds and you have poor compression on one or more cylinders, it's a mechanical issue.

HTH..........ed

 

[nightimefishn]

Re: low compression in #3 and possibly #4 cylinder

Thanks Ed, Thats what I was afraid of.Just a little wishful thinking I guess. I am just a very frustrated new boater. Cant get a hold of the mechanic who told me head gasket that doesn't even exist on my inline 6!!

 

[daveswaves]

Re: low compression in #3 and possibly #4 cylinder

Can electrical issues cause incorrect compression results? I don't think so but I am really not sure.

This was answered in your other post, you will have to rebuild your engine, its not the electrical system, its mechanical.

 

[sschefer]

Re: low compression in #3 and possibly #4 cylinder

Thanks Ed, Thats what I was afraid of.Just a little wishful thinking I guess. I am just a very frustrated new boater. Cant get a hold of the mechanic who told me head gasket that doesn't even exist on my inline 6!!

Yep, many things can cause bad compression but a cylinder cover gasket isn't one of them.

Normal wear and tear is worn rings and excessive taper. This is a natural effect over time but can happen quickly if the engine is subjected to extremely dirty air conditions. Boat engines without any intake air filtration didn't last long when Mt. St. Helen's blew.

Abnormal would be a lean conditon that has burnt a hole in a piston or the lack of oil that results in scoring the cylinder walls.
Overheating causes piston and cylinder expansion and the excessive forces will score cylinders and possibly cause the engine to seize. Any of the abnormal items I've mentioned have the potential to seize the engine.

FYI, too much oil can cause a lean condition. Too much fuel fouls plugs but usually provides enough lubrication even if there is a shortage of oil. Correct fuel supply and not enough oil can cause scoring. Excessive oil mixtures above 25:1 won't atomize correctly and result in a build up of oil in the cranckase. That could result in broken rings and/or a bent rod.

Now, if you ever find your mechanic you can go in with a full load of ammo and make him pay you! .. LOL...