Force 85 Serious Trouble HELP ! ! !

[Farrelloa]

I have an Force 85hp outboard which was stolen and recovered, when it was stolen the engine/model numbers were removed and now I need to order a new piston for it and need these numbers. Is there any possible way to find out what model and year it is. Also is it possible to get a piston for a different model to fit. (It needs machining anyway) <br />Any help much appreciated.<br />Regards<br />Aid

 

[walleyehed]

Re: Force 85 Serious Trouble HELP ! ! !

Sorry to hear about that...<br />Do you know approximately what year????

 

[Farrelloa]

Re: Force 85 Serious Trouble HELP ! ! !

Not to sure im probably the engines 3rd or 4th owner. Is there any way of telling without the numbers e.g. styling

 

[walleyehed]

Re: Force 85 Serious Trouble HELP ! ! !

That's a tuff one... If it's the 3 cylinder, it's a 3.312" std bore, Wiseco piston P/N 3029PS.<br />Over-size pistons end with P2, P3 and P4 representing 20, 30, and 40 over..<br />This would be 1984, thru 1989.<br />How many splines does your prop-shaft have, and can you get a P/N off of the prop..I may be able to classify it that way...

 

[Farrelloa]

Re: Force 85 Serious Trouble HELP ! ! !

Yep thats the one. Will any piston fit

 

[walleyehed]

Re: Force 85 Serious Trouble HELP ! ! !

See if you can count splines on prop shaft or get a P/N off of the prop...we may be able to pin-point it.

 

[Farrelloa]

Re: Force 85 Serious Trouble HELP ! ! !

I will do, thanks for the effort. Ill have to check later on though.

 

[walleyehed]

Re: Force 85 Serious Trouble HELP ! ! !

Not just "any" piston will fit...It must be measured to be sure,(cylinder) and it also depends on the problem at hand..

 

[Farrelloa]

Re: Force 85 Serious Trouble HELP ! ! !

The piston threw a ring and has scored the cylinder, so it needs a oversised piston and a rebore.

 

[walleyehed]

Re: Force 85 Serious Trouble HELP ! ! !

OK, the only way you will know what piston to use will be to bore the first step of .020 over, and see if that cleans it up, if not, maybe .030 over will....depends on how badly grooved it is..<br />Also, if it has original Force pistons, for best results, find a OEM replacement, other-wise I would recommend boring all 3, and installing all new, same brand pistons..

 

[Farrelloa]

Re: Force 85 Serious Trouble HELP ! ! !

So will I be able to use any Force 85 wiesco piston ? ? ?

 

[walleyehed]

Re: Force 85 Serious Trouble HELP ! ! !

If it is the 3.312" bore, I don't see why not, but the wiseco piston requires a seperate wrist-pin bearing that must be ordered as well...P/N of that is W5216, and is about 13 bucks..new piston is around 80.00 for the wiseco.

 

[Farrelloa]

Re: Force 85 Serious Trouble HELP ! ! !

Yep it is the 3.312" bore im sure of it. I cant think why it would not fit

 

[walleyehed]

Re: Force 85 Serious Trouble HELP ! ! !

As long as the dome is the same shape and the skirts are of the same design, I'd say that's your bird.....

 

[dave in toledo]

Re: Force 85 Serious Trouble HELP ! ! !

hey walleye, i asked on this board last month if it was ok to only change two pistons to the new overbore size, mine is 40 over and one is 20 over, and use the original other pistons and was told it was not only ok but standard practice?/ is this right???

 

[walleyehed]

Re: Force 85 Serious Trouble HELP ! ! !

In my personal opinion, it's exceptable, but I don't recommend it because of changes in combustion, creating a dynamic balance issue....Yes, the pistons are manufactured to "weigh" the same as standard in most cases, it still creates a slight difference.<br />For average operation, it's ok. I personally am not happy with "average", so if I change one over-size, I change them all.

 

[dave in toledo]

Re: Force 85 Serious Trouble HELP ! ! !

thanks i was scared for a minute, the machine shop is almost done installing the pistons and bearings i will be assembling the rest of the motor, i thought oh s--t im in trouble, thanks again, i think average is all i can expect from force...