86 Merc 60 Hp problems

[SMOKNZ]

I have a 60 Hp Merc that has been having some bogging issues. I have never worked on these motors before so it went to the local stealer to be worked on. After $1200 and 3 trips it still bogs severly. They told me the top cylinder has a little lower compression and that there are metal shavings in that cylinder and that the motor is junk. I know they replaced a switchbox (or two, don't know if there are 2) and the stator and supposedly cleaned the carbs. The motor will work ok for a while and then will bog real bad and barely putt around. What usually happens in this instance is a small peice of metal will be in the top spark plug gap. Cleaning up the plug will help for a while. There is no tach in this boat so I have no clue what kind of RPM it is pulling but even when it is running ok, it doesn't pull real well. I do know that the fuel filter housing doesn't fill all the way up with fuel, is this normal?

Can anyone point me to where I should start? Pull the head and see where this metal is coming from? Fuel supply issue? Rebuild powerhead? I have some experience with 2 stroke sleds and their carbs, are outboard carbs similar? Are there maybe a reed assembly on this motor that has taken a crap. Everything I have learned about Merc engines thus far is from reading from this site. Thanks for the help!

Bill

 

[Laddies]

Re: 86 Merc 60 Hp problems

1. Always start with a compression check with the carb butterflies open, that means if you don't have a remote start button you must disconnect the throttle cable and advance the carbs by hand.
2. Never turn the engine over with the plug wires dangling, hook them to a spark gap or spark plugs that are grounded to the engine. This prevent the engine from inadvertant starting and gives you a chance to check the spark on all cyls.
3. If you have compression that is within 10% on all cyls. and you have good blue spark that only leave fuel as a problem, as I am assuming the timing is close as you stated that it did run for a while.

 

[SMOKNZ]

Re: 86 Merc 60 Hp problems

What about the metal shavings? Do you have any links to how to check timing on these motors. Thanks

Bill

 

[Laddies]

Re: 86 Merc 60 Hp problems

Melted aluminum could be to much spark, what did you find from the other tests?

 

[SMOKNZ]

Re: 86 Merc 60 Hp problems

The dealer did a compression test and the top cylinder was about 10 psi less than the other two. I want to say top was 112, and the bottom and middle were around 123. I'm going off of memory so my numbers may be off, but I do remember for sure it was around 10 psi lower than the other 2. I will reperform the test and report back.

Bill

 

[SMOKNZ]

Re: 86 Merc 60 Hp problems

Got some new info, the motor is an 1988, not a 1986. I got the compression test done. I found:

Top 100psi
Middle 127Psi
Bottom 127psi

While doing the compression check I verified spark to all 3 cylinders. As for the new parts, I can tell the stator is new (Nice new wires) and the switchbox was replaced. The trigger assembly looks older as evidence by the older wiring. I pulled the carbs off and all was very clean, no sediment in the main jets or bowls. I blew every passage out anyway with carb cleaner. What do I check next? Motor does run it just seems low on power then will bog completely out and barely putt around at WOT. This is when we find the specs of aluminum welded in the top spark plug. I read about the decarb procedure. Could my top rings be carboned up leading to the lower compression? I appologize for my earlier ignorance. This is a comunity boat owned by me and 4 brothers. They had been taking it to the dealer and I was always just paying my part for the service. I just thought I'd play aroud with it and see if I could figure it out. This is the first I've had my hands in this motor. Thanks

Bill