flunked compression test

[glennrow]

the marina just called and my 1991 force 120 hp has failed its compression test....cylinders 1,3, and 4 are all at 155. but no. 2 is at 20. they have yet to pull the head and investigate fully, but in your opinion does this sound terminal? i dont want to put much money into this motor as it underpowers my boat to begin with - but im not in a position to spend a bunch and repower at this point?

 

[byacey]

Re: flunked compression test

20 is pretty low, sounds like a hole in the piston or a blown head gasket; pull the head and that'll tell the story.

 

[baxtr]

Re: flunked compression test

had same problem last year with my 89 125. minimal compression on cyl 3. no money to repower the boat, or pay someone to rebuild.

bought a manual and rebuilt it all myself, parts and boring under 500 bucks, I did cyl 2 and 3 plus all gaskets. It was a lot easier than I thought it would be, just took a digital picture everytime I backed out a bolt

 

[Frank Acampora]

Re: flunked compression test

These engines are so simple that it is never terminal unless you throw a rod through the block.
First thing to do is remove the head and determine the damage.
If it is just a blown head gasket, the repair is cheap--about 40 bucks for a new one.
If it is just a bad piston and the cylinder is not scored, you don't even need to disassemble the engine. After you take off the carb and manifold, you can remove the big end of the rod through the reed block opening and push out the bad piston with the head off. Just be sure to retrieve all 16 rollers. Again--not too expensive. About 100 bucks for replacement piston with rings and wrist pin through WISECO.
If the cylinder is scored, then you must disassemble the engine and have it overbored. Around here that costs between 45-60 bucks per cylinder. Again an oversize piston assembly is about 100 bucks.
You don't need to replace all four pistons, only the bad one. The replacement pistons are balanced to factory weight, and the engine will never notice the extra displacement on the overbored cylinder.
So: If you are willing to do the work yourself, the repair is not too expensive. THAT"S THE BEAUTY OF CHRYSLER/FORCE ENGINES!

 

[baxtr]

Re: flunked compression test

Frank is right, it was a simple engine to work on, even with no expierence with outboard repair. Here in WI, it cost me $75 a cylinder to bore and hone. Make sure the machine shop does outboards!!! not just car engines. I also used wiseco pistons under 100 ea, I think the full gasket kit was around 80 bucks. I also did some extra things: t-stat, temp sensor, fuel pump, and a new exhaust plate, and still kept it around 500. To be honest, the hardest part of the whole thing was removing the original wrist pin from the original piston, they were pressed in, the new wiseco's have a circlip that retains the pin, much easier

if you do it yourself, and need any pics for reference, let me know. Mine was a 1989 125, but I would think basically the same.

It was a lot of fun doing it too, when she starts back up there is a Huge sense of accomplishment from doing it yourself.

 

[glennrow]

Re: flunked compression test

thanks for all the replies, ill keep you updated.

 

[glennrow]

Re: flunked compression test

marina says it needs a whole new core. after parts and labor, its gonna cost $3600 to get this turkey going again. that doesnt sound like it worth it to me - any other opinions ( i do not the the time or talent to do it myself )...anyone know of a decent used 150 hp out there?

 

[Kajun37]

Re: flunked compression test

if you cant work on it or dont have time.. then that is too much...go to ebay and do a search for "force outboard" and everything force will pop up..there are always nice freshwater forces for sale up from around where your from....good running force's on ebay go for anywhere from $1000 to $2000 usually..

you can part your motor out on ebay..good lower units sell for $300 to $450 in the summer time...electrical systems etc....or you can keep it for parts for your next motor.

 

[Frank Acampora]

Re: flunked compression test

I always get a little chagrined when I hear the prices commanded by marinas. I realize that they have overhead and must make a profit, but even without seeing the engine I can tell you that you can do much better. The shop is buying a rebuilt short block, charging you a margin on it and charging you 100 bucks an hour to install it. There is nothing wrong with that--they are in business to make money and that is pretty much the going rate. But you don't necessarily have to be the one to support them.

Example: I do not advertise but have a base of customers who will not bring their engine anywhere but to me for repair. This is entirely word of mouth because I do such a good job rebuilding and I am completely open and honest about what is needed. I show them the problem and tell them what repairs are needed. I also let them know up front that I do not have the equipment to diagnose and repair electronics so if that's the problem, they need to find someone else. I am not a mechanic but really enjoy working on outboards so I charge 400 labor for a complete rebuild, plus cost of parts necessary. I only do 1 or 2 engines a year. Its enough to satisfy my urge to play with them.

What you need to do (if you can't or won't do the repairs yourself) is to find someone like me in your area to rebuild your engine for you. Most likely you would get away with about 1,000 bucks. Ask at the local bass club. Those guys are usually tough on engines and will probably know someone. If you find the right guy, your engine will run better than new and you will be completely satisfied..

 

[irollint]

Re: flunked compression test

I have a 1987 force 125 and have been real happy with it for the 3 years that i have owned it but one of my pistons appears to be dead with no compression at all it sound like a fairly simple engine to work on and plan on doing it myself i was also wondering if you would concider doing it for me provided that i could bring the boat to you. i live in new york about an hour from PA. just wondered if you would consider it? or if you have any suggestions on manuals to get and tools that are deffinitely needed. my e-mail is newyorkcolors@optonline.net

thanks
butch

 

[baxtr]

Re: flunked compression test

There are also places that sell rebuilt powerheads for around 1200.00 if you want to just bolt something on that is allready done for you. I would still consider doing it yourself if you are at all mechanically inclined, it really is easy, take your time, take lots of pictures, and question the forums.


Yes irollint, it is an easy motor to work on, mine was a 86 125, complete tear down, re-bore and rebuild, never worked on a motor before, and it runs great now. also, if it is only the one cylinder, and the cylinder doesn't look scored bad you can pull the piston out and replace it without cracking the case open. pull the head to check your head gasket first, then check the problemed cylinder wall. Mine was a broken ring that got cought up between the wall and the piston, so I had to bore and hone.

 

[baxtr]

Re: flunked compression test

this is what mine looked like: