Any one know- Force motor A, B or C-- rings & pistons?

[brianvolt7]

1990 force 120

Does anybody know how to identify what motor I have. Model A, B or C. There is a sticker on the top left of the block that reads: 1201X90A
There is a stamp on the block in the lower left that reads: MG38488
The pistons are stamped with a 2

Model A is a different size rings than the B or C this is why I ask the question of A, B or C.

My other questions:
Does the 2 indicate original piston size or has this been gone through and bored out?
What is the size for stock piston rings or rings that will fit these number 2 piston.
What size ball hone do I buy for these calendars?
Is the MG number above the serial number or is there somewhere else I need to look?

 

[Frank Acampora]

Re: Any one know- Force motor A, B or C-- rings & pistons?

Do not use a ball or bottle hone. These engines have a "closed" cylinder bottom end and a 3 stone hone is the correct tool to use.

Not sure about A, B, or C, but I believe the 1990 120 was 3.375 standard bore so if you measure at 3.395 you will find out if it is .020 over.

 

[PaulO]

Re: Any one know- Force motor A, B or C-- rings & pistons?

Clymers states 70 - 150 HP:

STD BORE -

1984-1990A = 3.3130-3.3148

1990B-1999 = 3.3750-3.3762

Prior to 1993 the model number identified the horsepower,features,original boat manufacturer, model year and model revision- (Clymers)

The 90A to me suggests you have the smaller diameter. Check with PWNboat

 

[brianvolt7]

Re: Any one know- Force motor A, B or C-- rings & pistons?

He recommended that I have the block looked at by a shop. Now if I can just break it loose from the bottom half of the motor I can take it in. I have pushed it, hit it and pryed on it with screw drivers.

I am about ready to take a crowbar to it and try to pry it off.

A remanufactured unit is looking pretty darn good right now. But my wife is saying thats not in the budget, $1900 + shipping

 

[PaulO]

Re: Any one know- Force motor A, B or C-- rings & pistons?

Refer Post # 155