1990 175 HP Johnson Loss of Power/Slow to Plane

imported_Z

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Oct 18, 2006
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Looking for some help trying to narrow down the problem. Bought the boat this year. Ran fine early on, then was having problems getting the boat to plane out. Before was getting up to 55mph now tops out at 40. Takes several minutes to get there as opposed to 30 second prior. First time it occured, changed plugs (found a foul plug) and sprayed cleaner in the carb. Boat ran fine for about 30 hours. Now having the same problem. Changes plugs and sprayed carbs again, still the same problem. New gas, new filter on water separator. Don't know where to start. Thinking compression test, check each plug for spark. Any other suggestions. Planning to spend sometime this weekend trying to narrow down the problem. Thanks in advance for your help.
 

mikesea

Lieutenant Commander
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Oct 1, 2006
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1,830
Re: 1990 175 HP Johnson Loss of Power/Slow to Plane

your right on track,do the spark and compression checks,then post the results,I'm sure there will be answers for you. Good luck Bud
 

JUSTINTIME

Captain
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Sep 2, 2006
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3,284
Re: 1990 175 HP Johnson Loss of Power/Slow to Plane

sounds like something in the carbs also
 

Walker

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Jun 15, 2002
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3,085
Re: 1990 175 HP Johnson Loss of Power/Slow to Plane

Spraying the carbs is useless. Thety have to be torn down and given a "THOROUGH" cleaning.
 

imported_Z

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Oct 18, 2006
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Re: 1990 175 HP Johnson Loss of Power/Slow to Plane

Spark is good on all plugs however compression is another thing. On a cold engine, 90 on 5 of 6, the 6th did not register. Found water in the cylinder as I cranked the engine. Assuming a cracked block? Any other suggestions or should I just bring it to a wrench?

Thanks.
 

tashasdaddy

Honorary Moderator Emeritus
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Nov 11, 2005
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51,019
Re: 1990 175 HP Johnson Loss of Power/Slow to Plane

don't go thinking the worst. unless it froze, or ran hot. could be as simple as a head gasket. pull the head, and see whats going on. it will have to be done anyway. don't keep running it like that.
 

imported_Z

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Re: 1990 175 HP Johnson Loss of Power/Slow to Plane

it's the end of the fishing season. I'll have someone take a look at it and see what's what. At least I know where to start. According to the guy I bought it from, he had a new block put in about two years ago. Then it sat for two years. Thanks for your help.
 

tashasdaddy

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51,019
Re: 1990 175 HP Johnson Loss of Power/Slow to Plane

did you cahnge the impeller when you got it. the reason is they get hard sitting, even new and can fail. if you didn't do it this winter, after you find the other problem.
 

imported_Z

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Re: 1990 175 HP Johnson Loss of Power/Slow to Plane

will do. I will probably have the carbs rebuilt as well. I'm afraid after sitting for those two years I may have some build up.
 

imported_Z

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Oct 18, 2006
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Re: 1990 175 HP Johnson Loss of Power/Slow to Plane

After bringing the boat to a trusted mechanic, it turns out that two of the pistons are scored, upper left and lower right (facing the motor). Somewhere along the line they have been bored out before and the oversized pistons are already sloppy. Boring them out again would move the cylinder beyond spec.

I am looking for options beside replacing the powerhead and spending over 3K. I don't put a lot of hours on the boat and limited mostly to weekend fishing (freshwater). Live in CT and most of the lakes are realtively small. Thanks for your help. I have been reading this forum for the past two months and have learned a trendous amount.

Again the engine is 1990 V6 175 HP Johnson, model number J175STLESE. Thanks.
 

mokaction

Petty Officer 2nd Class
Joined
Aug 16, 2005
Messages
135
Re: 1990 175 HP Johnson Loss of Power/Slow to Plane

Go to http://www.lasleeve.com/master.html and have your cyclinder re-sleeve back to stock. I have done it a couple of time already. Saves you lots of money, or find a good old used block, what ever works.

Larry
 

reeldutch

Lieutenant
Joined
Feb 2, 2004
Messages
1,340
Re: 1990 175 HP Johnson Loss of Power/Slow to Plane

whats the bore size on the damaged cylinders?

look at the nr on the piston or just measure the bore.

there are at least 3 sizes pistons from wiseco for this engine.
if its bored over once if your lucky its only bored over 0.020
then there is .030 and .040

and there are may be more sizes from other manufacturers but im not shure.
 

imported_Z

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Oct 18, 2006
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Re: 1990 175 HP Johnson Loss of Power/Slow to Plane

What is the longevity of the sleeve. How long can you expect them to last?

I am looking into the bore size. Will get back to you.

Thanks for the advice.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1990 175 HP Johnson Loss of Power/Slow to Plane

Unlikely you have a cracked block. Check the head gasket first. It is also possible that you may have a water leak in the inner exhaust cover. Are the covers torqued to spec? Is there any porosity in the inner exhaust cover casting? Under high speed operation, it is possible to ingest cooling water into the exhaust chamber, then back into the cylinder-from the exhaust cover-esp the lowest cyl.
 

imported_Z

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Joined
Oct 18, 2006
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Re: 1990 175 HP Johnson Loss of Power/Slow to Plane

The pistons are .030 and very sloppy. Not sure the .040 would eliminate all the sloppiness. You can move the pistons in the cyclinder easily and see the rings. Whoever worked on this before did not perform the boring to spec.

The head gaskets were shot. The mechanic doesn't feel the larger piston (.040) will be large enough after he bores out the scored pistons. He is uncomfortable with using steel sleeves thinking the cyclinder walls will be too thin and crack as the motor heats up.

What are my options at this point? New block onl;y? What do others think about the steel sleeves? Are the sleeves just putting a band-aid on the problem. If there was an after market piston that was .050 would the walls be too thin at that point?

Looking to evaluate all the options. As always thanks for your invaluable advice!
 

mikesea

Lieutenant Commander
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Oct 1, 2006
Messages
1,830
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
 
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