Cracked block OMC

[alcan]

I have a 1990 40hp twin Evin. This motor had low compression on the bottom hole. I tried to remedy the problem with Seafoam, hoping it was just stuck rings. No luck.I removed the head and found that the #2 cyl was all scored up and the piston was shot. No real problem for me. Then I noticed that the block was cracked between the cyl sleeve and the water jacket. I thought this motor was toast at this point. I called my Outboard machine guy. No problem, he cut out the old sleeve, welded up the block. Bored out the block,pressed in a new sleeve. Bored both holes .020 over. This work turned out beautiful. I assemembled the powerhead last night. I am going to finish assembly and tuning today I will post the results.

 

[alcan]

Re: Cracked block OMC

Results exelent, runs like a top. This was the easiest and fastest overhaul I have ever done. My motor was only down for a week. Thanks to my dealer, They did the machine work in house, ordered all the parts I needed and had everything sitting neatly in a box for me satarday morning. All I had to do was pay. Usually I end up chasing all over for parts and have to wait for someone to ship. What a pain and I still end up paying. I have never used the VRO oiling system since I've owned this motor. So instead of just plugging of the oil side I removed the whole unit. I installed an easrlier (regular) style fuel pump. It works great. The Napa auto part dealers in my area get the boobie prize on this one. I called four differnt stores looking for sealant and cleaning products. Guess what, they don't have any stuff like that. It's funny they list it in their catolog. I guess their computers do not work too well. Of course no one I spoke with could think for themselves. Thats ok I spent my money some where else. That Permatex gasket remover is a joy to use. I thought I would post this for the archives. I have read several posts lately on cracked and pourous OMC blocks.

 

[93bronco]

Re: Cracked block OMC

are you saying that the corrosion around the sleeves of my 120/140 block can be cut out and welded back flush to edge of sleeve (not exactly in that order) & decked not exceeding specs.<br />then i could reuse the block instead of trashing it?

 

[alcan]

Re: Cracked block OMC

Hi 2K<br />What I am saying is this procedure worked wonderful on my block. If I didn't know the crack was there I might swear this was a new block. I have junked more than a few blocks with simular damage. If I were in your shoes I would look around for a shop that can handle this type of work. This work ain't cheep. But it is way less expencive than the alternative. I had one two inch long crack down the starboard side of the bottom cyl. Not only did they machine the inside of the bore bofore installing the sleeve, they also machined the the outside (water jacket area) as well. They actually checked and resurfaced all flat mating surfaces. The only place they did any real cutting was the repair area. I am sorry I can see your block so I don't know the the extent of the damage. It sure sounds like your block would be a perfect candidate though. I have read alot of your previous posts. I think you are one of the folks whom inspired me to post this sucess story.

 

[alcan]

Re: Cracked block OMC

One more little note. Because it is my personal motor and I am the mechanic, I am responsable for the warrentee. Which I have no problem with. If how ever if I were a dealer and someone asked me about this I might hesitate. Do to the warentee issue I might insist on a neww block. They weld up dragster engine blocks and all sorts of high tech stuff. Its good enough for me.

 

[93bronco]

Re: Cracked block OMC

thats just good to hear<br />i had thought the block was a lost cause due to the corrosion around sleeve mating surface with head, in some spots it runs down the sleeve <br />3/4 in.<br />i still have a good empty block(has a RPH #) that im going to swap all the internal parts to, i think it needs to be bored on one cylinder.<br />-<br />that will be after and if my current setup with the used 93 125hp block doesnt work.<br />i originally got a 90 day warranty for it, cylinders looked great so im not to concerned.<br />the cold comp is good, so only the fire up will tell.<br />but i have no problems with starting over.<br />had to take a break today.<br />-<br />thanx for the insite on the block issue, now i will keep it.<br />-<br />the other thing i have to do is fabricate a spark checker.<br />i had got one from stevens, but cant find it.<br />hopefully i didnt throw it out when i cleaned the garage of boxes.<br />any ideas on a quick fabrication?