Evinrude 90 -1988 Power Trim and Tilt  On Boston Whaler 17 ft Montauk Since New in 1988
In 1992 Had trouble with VRO horns,  seized motor two times, shut down both times before seizing fully, could tell it was coming by sound and losing power after dirt bike days as a kid.
pulled heads saw scoring damage on walls of bores. plugged VRO and ran 50-1 from then on Motor had about 300 hours in 1992 and I installed hour meter. Motor has 1452 hours on meter at teardown total
estimated 1800 hours. For several years compression was 120 on the left bank and 110 on the right, have used engine tuner many times, letting it soak in good . Compression has fallen off over years was 110 on left bank and 90 on right bank at teardown. This compression has been on the motor for about two years now. Motor has made a "ticking" sound for many years..rattling so the broken rings were no surprise. What was a surprise was how long this motor has run like this and if not for the teardown would still be running till something gave. sooner then later I think.Last few years lots of smoke on start up and motor sputters oil on water..Not Good. motor had been getting hard to start and would not idel well when in gear running crabbing trotline,would quit when running slow in gear,  however surprising motor would still idel at dock or sitting out in the water pulled into nutural. I did notice the  oil line plug in the VRO was leaking a bit so the carbs may have pulled some air in with the fuel,, It has had a way of "loading up" a bit when first opened up after a cold start and some warm up ideling up the no wake channel .then clearing and no more slugishness.

Another thing this motor was propped with a 21 inch pitch when new and I ran it that way for a couple years. It would pull about 4500 RPM at top speed..and on flat still water trimmed up,in late fall on a crisp day push the Whaler with me only and light gas and load to the magic 50mph mark on a timed measured mile.  Over propped it was from a dealer who had sold hundreds of BW's over the years. Someone there was slipping the day that prop went on and I was too green to know better.  One thing is for sure these V4 Evinrudes were tuff motors and could take a beating. This motor had plenty of power up to the day I took it apart last week, last rode it two weeks ago Feb 2005 and would wind up 4600 RPM that day with a proper 17 pitch prop which has been on the boat since 1993!  Basicly after 1995 I gave up on "details and piddleing with every little thing" and "just ran it" with 50-1 oil! Have changed lower unit oil and lubed motor though.. On third starter gear..!

Good piston from left bank 110 psi , some scouring in bore.
Second piston from left bank but thats where the bad rods from..

Scrored conecting rod on bottom crank journal toward bottom of engine on the left bank of cylinders.
Piston From right bank 90 psi on last ride before teardown compression test taken with warm engine all plugs pulled top ring broken, carbon deposited and scored in the bore by the port bad, side of piston has scoring also

Right bank second piston note carbon on wrist pin where rings were leaking long time to do this. Interesting I noticed a water leak on this bank at last ride so maybe.the .Thermostat is not working so good on the right side? Overheating?    plus the seizure VRO damage in 1992 1400 hours back. did no good. Did check thermostats about 6 years ago.

Small damage flake out of crank rod journal on lower cylinder left bank spot is about 1/10 inch wide .025 across and .006 deep. No crazing or checking in journals, but this "flake" gives me pause, if rebuilt will it flake off more ? Is there more damage below the surface.. I tapped on it to get it as big as I could and radiused it out with no sharp edge to break out more,  this is the journal the bad rod came off but the rod was damaged on its inner not touching this area, rod bearing surprisingly has no checks splits looks like it could be reused..not by me though. No the crank can not be welded as the weld (soft)  would flake right off. The cranks  surface has to be tempered hardened steel likeways a weld would cause a soft spot in the crank that would cause it to wring right off without all the proper heat treating and hardening
Another view of crank rod journal Can cranks like this be used again?? I know dumb question.. of course it can but no knowing how long it will last. I am looking for 3 years or 300 hours.then a new motor for sure.

A tip. I punch holes through a card board and put all screws and bolts in marked to where they go plus pictures and written notes for reassembly.. been doing this since I was a kid with dirt motor cycle engines 35 years back. the slightest reason could cause me to pull engines and split the cases on Husqvarnas, Hodakas, and a others.Even as a kid I could get them apart and back together again...cept for one Honda 50.. thats another story.
"The rest of the story"

Bottom Line the block can be rebored with 30 over pistons and it will work, even with some scoring left and the ports elongated a bit more on right bank because the broken rings caused a wear  spot there The bad rod replaced, 4 new pistons, new center and bottom bearing and new rod bearing for sure as good practice, but the crank is suspect..I belive it will last at least a couple of years,, my question is weither or not to go for a rebuild and 800 dollars.. or sell it off in parts on Ebay and buy a new motor Mercury 60 4 stroke or 90 2 stroke no Optimax though for me..I still dont trust oil injection   I await your verdicts on this one.. the 800 dollars and my time is no problem if you think It can still go a bit.. I know no theres no real way to tell.. seat of the pants flying...as such. Oh yes new rod bolts and seals for sure if I go for a rebuild. In back corner of above pic is the assembly tool for these motors.. I may do a page on the instructions for those whom dont have them and get one of these..really not needed if you do take painstaking care to realign rod caps.. mine were perfect on both sides, however it does fit into the crank case and stablize the rod on the crank as you put the torque on..as the pressure goes on to the case ..Rod Bolts... little bolts with sooo much torque ..

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