Re: 1990 175 HP Johnson Loss of Power/Slow to Plane
The big CON or UNFORTUNATES with the 175 since 1986 is the std.bore size.The 150 hp and a few other v-6 engines have a 3.50 bore(std)the 175 and 235 were increased to 3.625(std)That made a very thin sleeve wall.This caused problems like ,poor cyl,head seal,delamination of the sleeve from the cyl casting,ports cracked and more.Now add any oversizing and the slightest problem like overheating ,these engine blocks did not tolorate.The fix,yep,you can resleeve,that cost 200 a hole 10 yrs ago,add to that the 125a piston .You have to compleyly tear that engine apart and inspect every port for hairline cracks,closly observe if on the outer portion of the cyl.where the head gasket would seal,check and see that there is NO spacing between the steel sleeve and alum.cast.If the block has minimal machine work to be done ,you need to determine if its worth it to you to rebuild the powerhead.Is the remaing engine parts in good shape. How is the trim unit,lower unit clean.There are many different sleeves out there that would put your block perhaps BETTER than new,but machine work dont come cheap.I know a guy that had 6 sleeves done ,these were called flanged sleeves,this eliminated the headgasket sealing problem in that the whole sleeve was designed to allow only the steel sleeve to be the sealing surface. Another poster gave you the LA sleeve site,more info can be found there.At 15000 dolars for an outboard,I can see why some people,especially those doing the work would spend the bucks to rebuild.But you wont get it back in resale so you have to expect to own and use it.Other options.Get another Johnson or evinrude v-6,in good shape,it uses same controls so its a bolt off-on deal.You will have a spare lower unit and electrical parts.Or,maybe find a good used powerhead,but a used powerhead,is a shot in the dark.Sleeves are not a band aid.AS said,some make it better than new.I dont know how easy it would be to buy a NEW OMC block,the crossflow engines have not been built for some time.Check ebay,I will too.Ideally,the cylinders need to be checked and bored to accept pistons and rings that fit to speck.I prefer to keep all cyl.the same,but not necessary,I feel they run better when even.If you know a machine shop,find out what the cost of installing sleeves,and decking the block.If your mechanical inclined,you CAN do the rebuild yourself,thus putting the savings into the parts and machining