1995 Johnson 150 OR Temp Switch?

[Yankee30]

So here is part 3 of my issue. For the last few weeks I have been trying to figure out why I have a constant alarm after 3/4 to full throttle. So after replacing everything I can think in the fuel line, and unpluging the vaccum switch. I'm pretty sure that is not fuel issue and I pretty I don't have a heating issue since I can touch the heads when the alarm goes off without getting burnt.

So I started with the Temp Switch, unplugged one at a time and the first one (starboard side) and ran the boat and the alarm didn't go off. So I figure it's the switch and replaced it. So last night I was able to test it and after coming up to full speed the alarm goes off. I did not have time to try to unplug the port side since it was 11pm at night. So I guess the question is do I have to replace these in pairs or is there another sensor that I need to look for?

Thanks for all the info
Jim

 

[jonesg]

Re: 1995 Johnson 150 OR Temp Switch?

the problem with starting a new thread is no-one knows what the first 2 installments are.

 

[Yankee30]

Re: 1995 Johnson 150 OR Temp Switch?

Here are the other posts. I should of put them in this one.

Part 1
I'm getting a constant alarm when I'm 3/4 to full throttle. I know the alarm is either overheating or fuel restriction. I am going to try the fuel route first. I have replaced the cone filter and fuel separator filter. Now I am going to replace all the lines. Is there anything else that I might be missing. If it is an overheating issue (just had my pump replace 3 months ago) where do I need to start at? I tested the thermostats by boiling in the water to see when they opened (140-150) and they did. I can run 1/2 to 3/4 throttle with out any problems.

Thanks,

Part 2
Ok I am still getting a constant alarm at over 3/4 to full throttle. Here is what I have done so far. Please chime in if I'm missing something.
1. Changed out the fuel line from tank to motor and from motor to fuel filter
2. Both fuel separator filter and fuel filter at the motor
3. Taken out the fuel pick up out of the gas tank and everything is good to include vent and fittings
4. Changed out the Thermostats in case it was an overheating alarm
5. Unplugged the vacuum sensor to see if it would still alarm ( was told this would tell if it was fuel or overheating) the alarm still went off.
6. I can touch the heads for about 20-30 seconds before I have to move my fingers after the alarm.
7. I will be replacing the fuel bulb with an Johnson one today.

So the only other thing that I am going to do is replace the heat sensors on each head. Is there anything else I need to do to try to figure out why this is happening??

 

[Yankee30]

Re: 1995 Johnson 150 OR Temp Switch?

Link to part 1

http://forums.iboats.com/showthread.php?t=323607

Link to part 2

http://forums.iboats.com/showthread.php?t=326798

 

[wilde1j]

Re: 1995 Johnson 150 OR Temp Switch?

If the temp sw leads are grounded anywhere, the horn will sound. In fact, you can test the horn by grounding either of the tan leads. I would run a temporary lead from the motor to the control unit with the tan lead disconnected to verify the wire is OK before doing anything else.

 

[Yankee30]

Re: 1995 Johnson 150 OR Temp Switch?

I will give it a try, but won't that make the alarm go off all the time, instead of when almost full throttle. Well there is more vibration, I will check it out. Thanks for the info, this is my last shot and then I will take it to the repair man.

Jim

 

[Yankee30]

Re: 1995 Johnson 150 OR Temp Switch?

Wilde1j,

I looked over the wire and the one on the starboard side did have a nic in the coating. I taped it and will have to see if that was it come tomorrows test. Thanks for the tip, I would of never thought of it.

Jim

 

[Yankee30]

Re: 1995 Johnson 150 OR Temp Switch?

Back on the lake today to see if taping the wire worked and it still alarmed. Any other suggestions on what might be causing the alarm?

 

[Joe Reeves]

Re: 1995 Johnson 150 OR Temp Switch?

I assume that after installing the water pump three (3) months ago, the engine ran fine up to now? If so, that three (3) month old water pump could have picked up a plastic bag, cutting off the water supply, effectively cooking that new impeller, OR running thru sand silt that someone else stirred up would have an adverse effect on that pump.

At any rate, it would be a good idea to drop that lower unit to inspect that water pump.

Note..... If the engine starts to overheat, the alarm will sound long before the engine is hot enough to do any damage, hence the engine doesn't seem to be unusally hot at that moment.