1993 70 Force Powerhead rebuild

[cantcatch]

Well long story short, after 23 years of faithful service I need to rebuild my powerhead, I'm waiting on my FSM, but in the meantime I went ahead and torn it down. I've never rebuilt a motor before but have always wanted to have the experience. I have 20 yrs experience in fixing about anything, computers, appliances, electronics, etc.... I have a few questions:

I have unbolted everything I can see and I am still unable to remove the motor, any suggestions???

Any recommendations for piston brands and sources for parts? I've been reading some on wiseco but I let other use this boat at times and I'm a little concerned that they wouldn't allow the engine to warm up before going WOT...

Any other bits of advice from someone experienced in performing this project? I thought I would go ahead and rebuild the fuel pump and possible the carb and all the rubber hoses while I have it apart.

Thanks
chris

 

[pnwboat]

I've not actually done a 1993 70HP motor but I know that on all of the other motors I've done, the power head is held in place to the lower unit with a bead of silicone adhesive. Sometimes it's a real bear to break loose. There is an adapter plate that is bolted to the bottom of the power head, then a thick bead of silicone is applied to the bottom of the adapter plate where it mates up to the lower unit. You have to pry between the adapter plate and the lower unit to break it free. Just be careful and don't break off a chunk of the adapter plate or the lower unit when prying. You might try and tap a single edge razor blade in between the adapter plate and lower unit to cut through some of the silicone adhesive to help free things up.

 

[cantcatch]

Thanks, I finally got it removed and tore down and bored out to 20 over. Anyone have any recommendations of a rebuild kit or a good source for parts?

 

[cantcatch]

Received my rebuild kit yesterday. WSM pistons 20 over. When trying to install all the needle bearing into the rod there doesn't seem to be enough clearance for all 26. Anyone else ever have this issue? Maybe I'm not getting all the needle bearings started at the same time? Heck if I know....

 

[pnwboat]

What are WSM pistons? I'm assuming that you're referring to the bearings on the wrist pin? I know the Wiseco pistons require different wrist pin bearings and spacers. Part# WP29-1 is the kit with the bearings and spacers. About $12 a set per piston.

 

[Frank Acampora]

Put a little grease inside the small end of the rod. set the rod on a non-porous flat surface. Now insert the needle bearings one or two at a time. Be certain the bearings are approximately vertical. The last bearing will press in with a very slight snap.

Now: There are two different pistons made in that diameter.--one with a small wrist pin and one with a larger diameter wrist pin. I am almost sure that your piston has the smaller diameter wrist pin. If you received or ordered the wrong piston and bearing kit, it will not fit your rod.

 

[cantcatch]

Thanks for the advice, ended up calling WSM, seems they had an issue with getting some needle bearings that were too large, they sent me a new set and the motor is back together.

I've read where some retard the timing after a rebuild, but the FSM doesn't say anything about it.....opinions needed? Should I do this?

 

[pnwboat]

I've seen that comment about retarding the timing too. I've never done it and never had a problem. Just don't abuse the motor during break-in, double the amount of oil and you should be good to go. Once it's broken in, go back to normal fuel/oil ratio 50:1.

 

[cantcatch]

Ok thanks.