95 Force 70hp Rebuild

atengnr

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Well mine was also “good running condition” so honestly that doesnt mean much. Need a motor with a good powerhead.
 

racerone

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When a motor " runs " does not mean " good running condition.-------On more than one occasion folks have said----" wow it never ran so nice before " after proper repairs.
 

atengnr

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Yes sir. My engine ran just fine actually, even under a load, and pushed my four winns 16ft with 4 passengers to 32 mph!

How do you think my 68 55hp would perform compared to the 70hp force?
 

atengnr

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Well Im pretty settled on rebuilding. If i get 5 years or more out of it then Im happy. Plan to get the block to a machinist next week. My quick bore check near top of bores looked like they were near end of spec for standard bore.
 

jerryjerry05

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Take the specs for the standard piston and have them compare to what's there.
They can then tell you how much it needs to be cut.

Once you get past .030 you'll need to re-jet.
 

atengnr

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I also notice that the ring land between rings on cylinder 2 was cracked in a section and broke off when i tried to move it. Could this motor have been over-revved as cause of its demise? I dont see alot of carbon on ring grooves or pistons crowns. No sign of detonation either. For the short time I ran it in 2019, when I checked the plugs (multiple times) it was rich appearing if anything. I cleaned high speed jet in spring when I first bought, but nothing looked amiss.
 

atengnr

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Can I buy rod bearings that have needles that will remain in the cage when moved around?
 

jerryjerry05

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Don't think so.
Get OMC's assembly grease.
It sticks the bearings to the site and then washes away fairly quick when the
motors ran.
Regular grease can cause failure.

ebay "OMC assembly grease"


MERRY CHRISTMAS!!!
 
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atengnr

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Well took block to a machinist whos well versed in outboards, and he found cracks in the exhaust ports in aluminum. States that this is a problem that he sees. Am I likely to find used blocks cracked like this?
 

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jerryjerry05

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This is the first time I've seen cracks like this.

I have seen them in a 50hp Mercury on the intake side.
 

atengnr

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Thanks. Well ive got another engine i could use the block from. This force engine is doing its best to talk me out of rebuilding!
 

atengnr

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No, im not asking for nor did i advice about replacing the engine with another. Thats not my plan.
 

topgun3690

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No, im not asking for nor did i advice about replacing the engine with another. Thats not my plan.

I like your plan to rebuild, especially if you have the parts on hand and do your own work. Post #10 had some great advice in it. Good luck!
 

jerryjerry05

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Go with the rebuild.
Try to figure out why it went bad in the first place?
Then work around that.
Any questions, just ask.
 

atengnr

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You all have helped tremendously and I thank you.

so, what I see is that someone popped in a standard size wsm piston on cylinder 1 and i think left scoring from original failure. Cylinders 2 and 3 had cracked rings on ring #1. Piston 2 also had a failed ring land which broke off in a section. Engine ran good, and spark plugs are rich if anything. Would an overheat cause this ?? Overrev??
 
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jerryjerry05

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Overheat could cause it?
Bad impeller?
Wear plate worn?
Running with an air leak?
Plugs too hot?
Running premium fuel.

Running wide open?? outboards are designed to run at high rpm's.

Once you start the actual rebuild, start another thread , it'll be easier to navigate through without these posts.
 
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