Rebuilding 1987 Johnson 175

[jimmyebay]

Bought this motor. One cylinder is pretty damaged from eating piston ring. Appears motor is just that worn out and caused it. Took to machine shop. .064 over sized pistons available from wiesco and they believe will machine out good. Question, can I put .044 over in other cylinders and .064 in just the one?! Wiesco pistons balanced as weight? Cause vibrations?! Thought about resleeving that hole but figured why when a piston available. Can always be sleeved later. Also, oil injection system been bypassed. Don't appear motor failed from lack of lube. What ratio should I mix it? Thanks

 

[gm280]

WOW .064 thousands oversize? I've never ever heard of going that large with any rebuilt engine. Personally I would go for sleeving that cylinder if it were mine. But since the other cylinders are at .044 over, maybe look for another block all together? If I couldn't find another donor block, then I would shell out the money to sleeve all the cylinders back to standard spec sizes. But that is just my warped thinking...

As for the fuel oil mix, 50:1 (fuel to oil) is the usual mix for near about every 2 cycle OB engine now!

 

[racerone]

????-----Is the block original to the motor ??-------Is the block 3.500" bore or is it 3.625 bore--------------Are you and the shop 100% sure you can get a 0.064" O/S piston for a 3.625" block ?????????

 

[jimmyebay]

It's a 3.625 bore. There all standard bore right now. Called company out of Florida ad they said .064 is available from wiesco. Just talked to them and double checking if that size is available. Ment I would bore other cylinders .030 out and just the one to .064. Would that cause issue? Rough run? Guy at this company said wouldn't hurt anything. Sleeve might be way to go. Just seems like more to go wrong with machine shop error with sleeving then just a bore out

 

[racerone]

Call them again and ask them to check if 0.064 " O/S is available for that block !!!

 

[jimmyebay]

Waiting to hear back to verify available. Keep ya guys posted.

 

[emdsapmgr]

You can use the same carbs and jets up to .030 over. Anything more that .030 over and you should consider jetting up the carb throat that feeds the oversize piston. Make sure all 6 pistons are from the same manufacturer.

 

[V153]

Pretty sure you can only go to .040 with that 3.625 bore.

.064 pistons ARE available for the 3.5" block.

 

[Faztbullet]

.040 is the largest you can bore this motor....The sleeves are too thin to begin with and that why the big bore crossflows need special attention on the cooling system. Bad t-stats resulting in cold running = scuffed cylinder/s, bad t-stats and weak impeller result in exhaust bridge expansion seizing exhaust side of piston damaging rings and damage just escalates. If cylinder are lightly scuffed you can bore it .010-.020 and replace pistons, the reallbad one need to be bored to minimum(.030-.040) to clean it up

 

[jimmyebay]

Well this kinda put a damper in my plans. The guy again said can bore .064. Got on wiesco site. The 150 hp shows the .064. 175 is only .040. Looks like my cylinder damage will require more than .040 to get damage gone. This motor can be sleeve right? Anyone know a good brand and part number? Thanks

 

[Faztbullet]

It will be cheaper to find a used block than resleeve yours

 

[jimmyebay]

Just needs the one cylinder sleeved. That expensive to sleeve? Are the bearings and gaskets and rods the same for similar year 150 hp?!

 

[gm280]

jimmybay, if you can sleeve that one cylinder and clean up all the others to the exact same specs, then go for it. But otherwise try to find a donor block or even a totally different engine to strap on... Now if you have a real love affection for that particular engine, then do whatever you have too to rebuild that engine back to new. It is really your option and money being used. If it were mine, I would check out the sleeve route and go from there. But I wouldn't sleeve one cylinder and not size every cylinder to the same size. When all cylinders are of the same size, the engine runs better with each cylinder putting out equal capability. But that is just my warped thinking too...

 

[jimmyebay]

Well going to do some more researching and asking around with machine shops. Anyone know if the gaskets, rods, crank bearings ect are same for similar year 150's?

 

[Faztbullet]

Just needs the one cylinder sleeved. That expensive to sleeve?

Yes it gets expensive as the original sleeve is cast in place. The original would have to be bored out and new one slipped into place after block is heated. The $$ part comes into play as the sleeve does not come ported from manufacture and would need to have ports machined into it. If machinist has no porting experience he can turn a good block into junk with a couple of thousands in wrong place. This done by a good marine shop will run $225-325 including sleeve.

Are the bearings and gaskets and rods the same for similar year 150 hp?!

Gasket set is different.....

 

[emdsapmgr]

The rotating assemblies are the same-just the pistons/ringsets are bigger bore.