Force 120 Outboard Low compression - rebuild it?

[Stretch72cj]

Removed the powerhead today and removed #2 piston. New piston and machine work is required. Piston melted past first ring. Starting to create a list of items I know Ill need and with the gasket set I cant find what gaskets and seals are included. Seems like buying the kit will save money if all the gaskets are included. So far everything is coming apart well.

 

[racerone]

You must determine the cause of the " meltdown " or you will have the same thing happen again !!

 

[Stretch72cj]

That’s the pickle I’m in. Going to go through it all. Reeds looked to be in excellent shape. Bearings all look good too. No idea pervious maintenance or proper fuel/oil mixtures...seems like a decent unit to overhaul as the overall condition is good so far. Lower unit oil was clean as well. This is all new to me. I’ve dealt with diesel and some gas engines. 2 stroke is a new world for me.

 

[jerryjerry05]

You ever figure out the year?
The early model 120 has some things the later
models didn't.
The recirc system, even the gasket on the port cover
can be the culprit.
The carb not set right, timing off etc.

 

[The Force power]

That’s the pickle I’m in. Going to go through it all. Reeds looked to be in excellent shape. Bearings all look good too. No idea pervious maintenance or proper fuel/oil mixtures...seems like a decent unit to overhaul as the overall condition is good so far. Lower unit oil was clean as well. This is all new to me. I’ve dealt with diesel and some gas engines. 2 stroke is a new world for me.

Lets see... #1 scored #2 melted correct?
My money would be on the top Carb. (i'm sure if yours has two fuel pumps or just one?

 

[Stretch72cj]

The boats a 92 and the data plate is missing on the outboard. From what I’ve gathered it’s the 92 with the 90A, 92C carburetors. It has 1 fuel pump and the recirc system. I’ll try and take pictures of the pistons. Feels like a poor oil/fuel mixture or water was getting in. Noticed back sides of the pistons in the center above the rod have burnt on oil deposits too like they were too hot. I have to make notes and go through it. See if I can come up with a good story. Appreciate the input as well.

 

[Stretch72cj]

Stripped the block the rest of the way down and have attached pictures. Pistons are arranged 1-4 left to right. Meeting with a machine shop soon to go over cylinder repairs.

 

[jerryjerry05]

Keep us posted with what the shop says??

 

[Stretch72cj]

Keep us posted with what the shop says??

They can cut the cylinders at a reasonable price. He wants to go .030 over and needs the pistons I am to use. Im having a little issues locating the pistons that I would need. I see Wiesco 3151P3 is popular but found TSM performance pistons as well for a much better price. Any suggestions? The bore is 3.375" and the wrist pin appears to be 17mm. Here is the link to TSM's pistons. TSM Performance Appears those will work for my application.

 

[racerone]

The wrong propeller ( lugging ) the motor would cause that type of damage.

 

[Stretch72cj]

The wrong propeller ( lugging ) the motor would cause that type of damage.

I’ve heard that twice now. He has 3 propellers that came with the boat. I need to get the data off of them and find out.

 

[jerryjerry05]

Looks like TSM is the better way to go.
Probably get the bearing kits too. See if
the shop can cut .020 instead of .030
That will leave room for a future rebuild.

Was at work one day and a customer brings in a
boat and says the motor just blew up???
Comp low on 2 cyl.
He said I have no idea what happened???
Rebuilding the motor, I find a prop hidden under the seats.
25p chopper prop.
The guy evidently thought his 125 was a racing 125??