150hp j150sledb 1996

[Damifudo]

A couple questions for the johnny guru team.

The last time out my ocean runner 150 seemed to have a good miss to it. Ran with pretty good power and never stalled at idle but was missing at both high and low speeds. I started with spark plugs and they are a few seasons old they are QL77JC4 plugs. I bought the exact same replacements which now I have done some research they should be QL78YC. I did order the correct plugs but they will not be here for the weekend. So not sure if I should use the OL77 or wait for the QL78's. I know that the QL78s are a little longer and reach deeper into the cylinder but she seemed to run just fine on the QL77JC4s. Opinions??? My repair manual even states to use the OL77's.

The other issue is I removed the thermostat housing to check the thermostats they have about 4 season on them. I run in salt water some and fresh water most of the time. The thermostats are plastic.

Now the part I don't understand is the part it calls for is 0435491. When I look for a replacement on I boat they don't list my 1996 year as a replacement part for sierra or Mallory. Which happen to sell for half of what the OEM part sells for. The dealer wants 32.00 a piece for them. Whats the difference between OEM and Sierra? Why is my year not listed?

Thanks for any comments.

 

[bob johnson]

Re: 150hp j150sledb 1996

you can use the thermostats from 95 and up in all those motors... I even bet you could use those one piece white thermostats in v6 60 degree loopers all the way back to 1993....even though the book shows them as being several pieces.....the one piece plastic t stats are an "improvement" and I think they are used in the 60 degree looper motors up into the 2000's. your manual...if you have one says that the use of NON suppression spark plugs will cause ignition problems!! here is what the thermostats looks like now:OMC 435491 Thermostat Assembly Evinrude Johnson 10 175HP | eBay

 

[Damifudo]

Re: 150hp j150sledb 1996

Thanks for the input I picked up factory thermostats today and I am going to use the OL77JC4 because thats what the Johnson tech at the factory repair technician told me to use. He said he has had better luck with them than the Q78Ycs. He said they are pretty much the same plug.

 

[Damifudo]

Re: 150hp j150sledb 1996

I changed the plugs and thermostats and added some seafoam to the tank.

She ran better and runs good at high speed to full RPM 5200. She takes off strong on anything above 3000 rpm with no sign of a miss fire . She has a low speed miss below 3000 RPM and down. The seafoam is in the tank with about 10 gallons of fuel. Should I continue to run the tank and let the seafoam do its work on the low speed jets? Should I stop and just break down and take it to a mechanic and get the carbs rebuilt? I will say she is smoking pretty good with the seafoam but I think thats normal running on a heavy concentration of seafoam.

I also have never touched the carbs in the 4 years I have owned it. Is it just time ?

Opinions???

 

[bob johnson]

Re: 150hp j150sledb 1996

5800rpm is better.....get another prop!! since you just did it, let it run for several tanks of gas......check the temps.....if you arent running hot.....let it be.....you could adjust the needle and give it a try....if no change, adjust back to what it was...then try another carb...and so on.....if after the seafoam is done you could check the plugs...if one is sooty, lean out that carb...if you pull the ncarbs all apart you run the risk of more issues when they get reinstalled.....bad gasket fit...misadjust float, or idle needle...more stress on the plastic carb bowls( they warm from to tight torque on the screws).....now if the motor was running very badly....its a great idea to rebuild the carbs...good luck

 

[Damifudo]

Re: 150hp j150sledb 1996

Feeling depressed as my 1996 is not up to her normal sparky self. At low speeds she has a dead miss. I have installed the things I know how to do. Spark plugs and Seafoam which as gotten her up and on her feet in the past. I have watched a ton of You tube videos on carbs and cleaning for a 150hp Johnson.

The part that had me really depressed is the Compression check I did yesterday after going to Harbor Freight and getting a new tester. My numbers warm or cold are very low. R 89-89-82 L 85-82-81 . I have always babied this motor with good fuel and oil. Only had the over heat alarm go off a few times with grass and shut it right down. Even now she seems to run cool with no alarms.

Is Johnny on her way out? I am no mechanic so I think its time for a professional. I hope he can tell me some good news. Going to have to wait till Monday. I will try to get another compression tester just to be sure its not the Top Quality tool from Harbor Freight LOL .

The one thing I read that I didnt do when I took the compression test was to open the throttle to wide open. Can that make much of a difference?

 

[Chris1956]

Re: 150hp j150sledb 1996

compression gauges are sometimes inaccurate. Your compression is within 10%, so your motor is good. The Seafoam may help, or it may not. See if you have air orafices on your carbs. I have them on my '98, and they can get dirty. Give 'em a blast of gumout spray cleaner. If that doesn't fix the miss, a carb rebuild is in your future.

 

[bob johnson]

Re: 150hp j150sledb 1996

Feeling depressed as my 1996 is not up to her normal sparky self. At low speeds she has a dead miss. I have installed the things I know how to do. Spark plugs and Seafoam which as gotten her up and on her feet in the past. I have watched a ton of You tube videos on carbs and cleaning for a 150hp Johnson.

The part that had me really depressed is the Compression check I did yesterday after going to Harbor Freight and getting a new tester. My numbers warm or cold are very low. R 89-89-82 L 85-82-81 . I have always babied this motor with good fuel and oil. Only had the over heat alarm go off a few times with grass and shut it right down. Even now she seems to run cool with no alarms.

Is Johnny on her way out? I am no mechanic so I think its time for a professional. I hope he can tell me some good news. Going to have to wait till Monday. I will try to get another compression tester just to be sure its not the Top Quality tool from Harbor Freight LOL .

The one thing I read that I didnt do when I took the compression test was to open the throttle to wide open. Can that make much of a difference?

those numbers are fine for that V6 motor....I doubt they were over 90 when new!!! that v6 didnt have high compression!!



the V4 ran to the 125's or so...but not the V6's........no wait.....that motor is shot....ill give you $200 for it!!!!!!!!!!!!!!!!!!!!!!!!!


bob

 

[Damifudo]

Re: 150hp j150sledb 1996

Bob you made me feel so much better I hope your correct. I know it is a low compression motor. The strange thing is it runs fine at higher RPM. No miss at all. I tested each plug with a spark tester and have good spark on all six plugs. I have no over heat alarm. I still have about 4-5 gallons of Sea Foam in the tank. Its been sitting for about 48 hours. A friend of mine told me I should go take it out and run the snot out of it. He thinks its do to the fact that its been sitting for a few weeks while I was on vacation and that the next two times I ran it was entirely in a 6 mile an hour zone. He thinks one of the idle jets is clogged and he says if you run the snot out of it with the sea foam that it will probably clear it out?

Like you, he said just keep an eye on your temperatures. He also said some good WOT runs Might help my compression numbers and clear it out carbon with the sea foam.

My question is will it harm it to run it hard with the sea foam in it? I just changed the plugs over from QL77JC4 to QL78YCs. I have about and hour on the QL77JC4s and they all look about the same. None are dry.

 

[Damifudo]

Re: 150hp j150sledb 1996

I am going to do a good decarb and then take it for a good run. Heading to the auto parts store for a couple cans of Sea Foam. I am going to get some fuel line too start changing out the fuel lines. I will have to check on the sizes I need.

 

[Chris1956]

Re: 150hp j150sledb 1996

The main fuel line needs to be 3/8" ID

 

[bob johnson]

Re: 150hp j150sledb 1996

I am going to do a good decarb and then take it for a good run. Heading to the auto parts store for a couple cans of Sea Foam. I am going to get some fuel line too start changing out the fuel lines. I will have to check on the sizes I need.

there is no carbon problem with your symptoms.......carbon issues are in the cylinder and in the rings on the piston... they have nothing to do with carbuerator issues!!!! if the idle passages are glogged with an undisolvable debris...the seafoam will do nothing to it...it might not help even if the debirs was gummy -varnish -dried oil .....you could carefully screw in all your needles to their seats counting the turns.... to make sure they are the same...(mostly that one is not way less than the others) and then crank them back if they are all the same..the fatcory manual has the amount of turns to start with......it varied by year. I have a 1995 manual and a 1997 manual for the same type motors.... one is like 3.5 turns the other is like 5 turns...... for 1996 who knows!!...bob

 

[Damifudo]

Re: 150hp j150sledb 1996

I am amazed at what this sea foam did to my engine. It runs so much better. Quiet and almost new like. I took it out for a few good WOT runs after the treatment and then had to idle back almost 2 miles though the 6MPH zone. It never even hiccup once. I going to try to do a compression check tonight to see if my compression might be better too.

This stuffed saved me a trip to the Mechanic and probably a bunch of money too. Plus the most important part it has me back on the water again. Does a bit of a happy dance!

 

[Damifudo]

Re: 150hp j150sledb 1996

I used a friends compression tester and was reading between a 115 and 120 PSI per cylinder. The Harbor Freight crap was reading about 30lbs low. Circular file that tester! 120 was what I was reading when I got the engine so I am pretty happy with those readings. She has been running strong since I sea foamed her.

Watch compression tester from Harbor Freight.