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1992 Johnson 150hp Fast Strike

G

gbillin

New member
My 92 Johnson 150 Fast Strike has been running great until yesterday. Motor cranked fine, but I immediately noticed something wasn't right because the engine speed barely went up from idle using the fast idle lever. Motor would run at idle but was rough and didn't sound right. When I put it in gear there was almost no acceleration - barely above a good idle at full throttle. The motor had some vibration and seemed like it wasn't firing on all cylinders. I ran it two weeks ago and it ran great. I filled up the tank with fresh fuel the night before. I checked the plugs when I got home and they looked okay and all were firing - at least enough to get a spark turning the engine over.

Any suggestions on what to start checking? My first thought was ignition problem but I really don't know what to check first.

Thanks for any all help,

Gary
 
Re: 1992 Johnson 150 Fast Strike

!st--check compression
2nd--Fuel!!!

How often do you run the boat? Do you use pump gas with up to 10% Ethanol? Do you use a fuel stabilizer on a regular basis?
 
Re: 1992 Johnson 150 Fast Strike

also check the cables from your control box back into the motor make sure they are functioning properly

if the compression comes out positive i would rebuild/clean the carbs
 
Re: 1992 Johnson 150 Fast Strike

Thanks for the quick replies.

I don't know the compression and I don't have really have any way to check it.

I know a lot of people have had fuel problems with the ethanol blends that we have here, but until now, I've had no problems with my motor. I filled the tank Friday night and Saturday morning is when I had the problem. All fuel here is 10% ethanol.

I did check the control linkage and everything appeared to be operating correctly. The fast idle lever and the throttle were both operating the linkage on the carburaters. Nothing appears to be loose in the linkage.

The most surprising thing about this to me is that it came on so sudden. I used the boat two weeks ago and the motor ran great. Now, it will crank but it just won't accelerate at all. I read a few comments on the net about this motor and several mentioned the same problem. They mentioned the power pack in the ignition being a weak link. Does anyone know anything about the ignition on this motor and a way to check the power pack?

Thanks for your help,

Gary
 
Re: 1992 Johnson 150 Fast Strike

i tried looking through the forums to find a write up on how to check the power pack. i have seen joe reeves post how before wait till he looks at this topic and i am sure he will let you know how.
 
Re: 1992 Johnson 150 Fast Strike

If it were mine, based upon your symptoms I would suspect water in the fuel. I would remove one of the drain plugs from one of the carbs and see what comes out.
 
Re: 1992 Johnson 150 Fast Strike

Comprssion gauges are rather cheap, available at Wal*Mart, K-Mart, automotive parts type store, etc..... purchase one.

Check compression... should be approx 100+ psi and even on all cylinders.

Check spark... should jump a 7/16" gap with a strong blue lightning like flame..... a real SNAP! The 7/16" gap is important!!

No spark tester? Build this one, it'll come in handy more than once.

(Spark Tester - Home Made)
(J. Reeves)

A spark tester can be made with a piece of 1x4 or 1x6, drive a few finishing nails through it, then bend the pointed ends at a right angle. You can then adjust the gap by simply twisting the nail(s). Solder a spark plug wire to one which you can connect to the spark plug boots, and a ground wire of some kind to the other to connect to the powerhead somewhere. Use small alligator clips on the other end of the wires to connect to ground and to the spark plug connector that exists inside of the rubber plug boot.
Using the above, one could easily build a spark tester whereas they could connect 2, 4, 6, or 8 cylinders all at one time. The ground nail being straight up, the others being bent, aimed at the ground nail. A typical 4 cylinder tester follows:
　
..........X1..........X2
.................X..(grd)
..........X3..........X4

If the two above areas are as they should be, and if that engine is carbureted, clean the catburetors.
 
Re: 1992 Johnson 150 Fast Strike

Does the motor idle at all? Does the motor bog down when you go to accelerate? You may have dropped something in your fuel tank. When was the last time your had your carbs rebuilt? You may have gotten some bad gas to.
 
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Re: 1992 Johnson 150 Fast Strike

Well, I picked up a compression gauge on the way home from work today and checked the compression on all cylinders. Gauage read between 100 and 110 on all cylinders so I feel compression is probably good.

I also got an adjustable ignition (spark) tester and checked the spark on all cylinders. I set the gap at 7/16" as Joe suggested and I got a strong spark on all cylinders. I could easily hear it snap when it sparked so I concluded that the ignition appears to be okay also. Spark plugs all were a little black but were not burned or fouled out.

The only other thing I knew to check was the fuel supply so I took off the fuel line where it splits to supply the three carburetors on one side of the engine and stuck the fuel line in an empty bottle. When I turned the engine over, the fuel pump was pumping a good stream of fuel through the line so I conclude that the fuel pump is working okay. Fuel looked okay and smelled fresh to me.

Next, I took the drain plug out of the top carburetor - nothing came out. I removed the plug from the middle and lower carbs on the same side and fuel came out. This has me concerned that I probably have at least one clogged up carburetor.

Tigershark, to answer your questions: yes, the motor will idle but it wasn't the normal smooth idle I usually have. It was rough and died several times. The engine would only barely speed up using the fast idle. It seemed to me that it was worse than just bogging down, it never really would accelerate at all. I have never rebuilt the carburetors - I've had this boat five or six years. I filled the tank with fuel the night before, so I assume it was okay.

Any suggestions on anything else I should look at?

I really appreciate all the responses. You've been a great help.

Gary
 
Re: 1992 Johnson 150 Fast Strike

Strongly suggest that you remove, clean, and rebuild all of the carburetors so as to start anew.

You did an excellent job of trouble shooting.
 
Re: 1992 Johnson 150 Fast Strike

re-building the carbs is more routine maintenance nowadays. It should be done once a year or at the start of the season. That should solve your problem.
Its July!!!! Time to enjoy your boat!!!!
Happy 4th
 
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