1989 Johnson GT 150

[Scotty B]

Hi guy's I just bought my boat last summer from the original owner, who always had the dealer service the boat and motor actually stored at marina every winter.

My question is it sat for 2 years previous to me buying it, although the motor seems to run real strong no hesitations or anything like that when I changed the plugs last year after running it a couple times out I pulled the plugs to read them and see how they looked and four out of six had nice color to them but one plug on each side were not as dark and a little on the light side for my likeing.

do you think that maybee the carbs need to be cleaned or am I just making somthing out of nothing??? I planned on having my local marina look it over this winter for some peace of mind but unfortunely I don't have the money to send it out.
Just looking for some feedback thanks

[J E R E M Y]

have you decarbed your engine since you have had it ?

[Scotty B]

No I just threw a set of plugs in it and ran it. I was thinking of running some seafoam in it but I wanted to hear what you guy's had to say.

I know the best thing to do is have someone go through the carbs but I work for my self and money is tight!!!! somehow my mortgage for my house and other bills are taking priority.

[J E R E M Y]

try decarbing it with evinrude/johnson engine tuner. your carbs should be ok unless fuel sat in the bowls for the 2 years.

[Scotty B]

I don't think that is the case as like I said in the first post, the marina winterized and stored it since it was new.

He had a house on the lake that the marina was at and the boat was never trailered.

that was the only draw back to the boat is that it didn't have the matching trailer because he didn't need it. He ended up getting a ez loader galvi jobber.

But I will look into that tuner/cleaner and see how that goes
thanks Jeremy

[Bassmeister]

Was the two plugs the bottom ones?

[Scotty B]

Actually no

if you were looking at the back of the motor it would be the top right
and I can't seem to remember for sure but I think it was the middle hole on the left bank, it's been a couple months trying to go on memory. but like I said I know for sure it was top right.

[ChampioNman]

I would rebuild the carbs according to the shop manual. And also test the recirc valves on the intake manifold.

[Scotty B]

ChampioNman I was planning on bringing in to a marina over the winter to have them go through it, but unfortunatly I just don't have the money to do that at the moment.

I just picked up the johnson tuner today and going to do that in the beginning of the week.
The motor idles fine and gets up out of the hole good also and I was reading 58.2 on gps. last season.

I also picked up a set of ngk's for it today, do you think there's a chance I should be ok???
How do I go about checking the recirc valve?? do I need any special tools??

[ChampioNman]

Take the NGK's back (they are for Mercs) swap them out for Champion QL77JC4's gap them at .030. To find your recirc valves follow the small vacuum lines from the cylinder side to the intake manifold just behind the carbs. Use a 5/16" socket and remove them carefully. They are a one way valve. To test them use a syringe ( I use a meat marinade injector, DEA won't let me play with needles) and short piece of hose. Fill the syringe with isoprophyl alcohol and try and push the alcohol through the nipple side if it doesn't push through the valve is Ok. Conversely if you can pull it through the back side it is good. There are small screens on the back side of the valve that may be gummed up. Put them in an aluminum pan and spray some engine tuner on them let them soak and clean the screens with a brush. Retest. If any are bad they need to be replaced.

[Scotty B]

Thanks again for the info I will check those valves out.

May I ask what the harm would be to run NGK's I have alway's ran them in other toy's like jet skis, snowmobiles, and my dirtbikes. You are not the first person to tell me this but then again no one can give me a clear answer why not to??

I also know a couple guy's in my bass club who only run them in the same motor with no problems.

thanks again
Scotty

[ChampioNman]

Check the plug chart on the top of the page. They will cause great harm to your VRO system you need the QL noise suppressor. Type NGK's for Merc/Mariner. Champ for OMC. No autolites seen too many blown motors using other brands.

[limerickjeremy]

i dont mean to hijack this but i just bought a similar motor and was wondering what oil is best to run in it?

[Bassmeister]

XD-30 or XD-50 and decarb yearly or 100 hours.