7.5 Johnson 1980 J8RCSS

[Nanich]

Hi I have a Johnson and I had some troubles with it. Perhaps some one will be able to help me out:

BEFORE TODAYS TROUBLES

1. Motor usually starts after a few pulls
2. Does not like going much slower then at the "START" speed
3. When starting it will often stall out a few times, before I get it going for good.

TODAY:

1. Starting like before, stalled a few times.
2. Gave it another pull and heard a "pop" sound.
3. I saw little white solid grease pieces floating around in the water.
4. After that, I could not get a spark or anything.
5. Changed the Spark Plugs, and it started right away.
5.5 Old sparkplugs are very dirty. There is grit on them, and they are wet/oily and dark. When I stuck a wire up the exhaust that is below the water, I noticed a lot of grease on it when I pulled it back out.
6. Took it for a spin.
7. Stall out when I slowed down, and would not start again until I took the sparkplugs out and retighten them.
8. Starts, but takes a lot of pulling to get it going. I also heard the pop again, and saw the white bits of grease in the water again.
9. Get it going again and take it back home.
10. When I tie up, I think the motor is a little warm.
11. I did notice that the motor heats up fast when I idle the motor at a high speed (I can tell but placing my hand under the water output,almost burning)) When I slow the motor down again, the water output cools down again.
12. I also notice how the water is coming out. WHen running idle fast the water stops for a split second every few seconds at a regular pace. When it comes out strong.

Problems suggested to me:
- I have a broken gasket some where.
- The impiler(sp?) on the water pump is partly broken.

any help would be great

 

[iwombat]

Re: 7.5 Johnson 1980 J8RCSS

I'm thinking it may actually be both. You certainly need a new impeller, and you may have to backflush to get some little bits of impeller out. Replace and see how badly it broke up if at all.

I'm also guessing it overheated at some point and you warped a head or blew a head gasket. A compression check should prove that one way or another.

 

[Nanich]

Re: 7.5 Johnson 1980 J8RCSS

At the beginning of the season I did overheat it to a point that the motor stopped, and I had to wait a long time before I could even pull the cord. I had forgotten to check the water pump to make sure it was working.

That was several months a ago and it has been working fine since, except for today. I am getting a "manual" tomorrow and will drop the leg and look at the impellar.

 

[Nanich]

Re: 7.5 Johnson 1980 J8RCSS

How do you do a compression check?

 

[iwombat]

Re: 7.5 Johnson 1980 J8RCSS

Sorry, but you're gonna slap your forehead after this answer.






With a compression tester.


Probably about $25-$40 or so at an autoparts dealer. Get the screw-in kind.

 

[Nanich]

Re: 7.5 Johnson 1980 J8RCSS

UPDATE:

I did the following things and this is what happened:

Bought a new gas tank, made sure the fuel was exactly 50:1


1. Emptied the oil from the gearcase:
a. Water poured out first then the oil came out pitch black

2. Dropped the leg.
a. The white creamy grease I mentioned before was all over everything inside the leg.

3. replaced impeller. It had a big set, but other then that it was fine.
4. I replaced all gaskets and seals. including the Gear Case Cover gasket.
5. I did notice that one of the seals on the Drive Shaft was torn before I removed it.

6. Put everything back together.
7. Motor would not start
8. plugged spark plugs back in.
9 Motor started with one pull.
10. Took it for a test spin. Engine temp seemed fine when going at a fast speed, but when I slowed down it heated up real fast. Almost too hot to touch.Then when I sped up it seemed to cool down again.
11. When I got back to the dock, and shut down the motor there was smoke/steam coming out of the "PEE" hole. I tried to restart it. The pull seemed slightly stiffer then normal and I could not start it.

My johnson book says that overheating is caused by:

1. defective thermostat (I will replace it)
2. low output of defective pump (replaced impeller, output is strong, but still does the on off thing)
3. damaged or mispositioned water passage restrictors. (Not sure what to do about this)

Any help would be great!

Donnie

 

[iwombat]

Re: 7.5 Johnson 1980 J8RCSS

Steam coming out of the tell-tale indicates a blown gasket. Compression test the motor and you'll probably find a blown head gasket. Overheat probably also means warped heads.

 

[Nanich]

Re: 7.5 Johnson 1980 J8RCSS

Well, I went to get a new thermostat. The parts dealer mentioned to me that it is more common for them to get stuck open instead of stuck closed. Well when I got the thermostat out is was very messed up. It was stuck open so far, that the other end blocked the hole. In otherwards it was so open it ended up being closed. I replaced it, and took it for a spin. Water temp stayed the same at fast and slow speeds. The motor seemed to run better at the slower speeds. I think I could even feel the thermostat kick in a few times, as the water from the "PEE" hole would suddenly cool down.

I think my problems are solved for now.... Now to make the damn thing start easier... I have been told to look at the carb

Donnie

 

[Nanich]

Re: 7.5 Johnson 1980 J8RCSS

UPDATE: I am pretty sure the temperature is fine on the motor. It is hard to tell when I can not get the thing started!!

This is what happened:

1. Pumped fuel into motor using fuel line pump
2. Motor starts in only a few pulls.
3. Motor stalls.
4. Motor does not start again. AT ALL, no spark or anything.
5. My fuel line has a fuel filter on it. I can see through it. I notice when I pump fuel into it, sometimes the fuel will flow back down.
6. I also notice that when I disconnected the fuel line I did not hear a little "hiss" that I normally do.
7. I bought a new line.
8. At one point I check the fuel filter in the motor. Looked fine and when I pumped fuel on the fuel line, I could see fuel come through.
9. When I checked the spark plugs they were wet. Dried them on my shirt.
10. When I tried to start it. Nothing every happened. I never got a sputter or anything.

I have been told that I may have flooded the motor. I did pump the fuel line a lot trying to keep fuel in that fuel filter on the line. My questions are:

1. If I did flood the motor what are the best steps to unflood it?
2. What is the best way to dry out spark plug? I was told with a lighter.
3. How many pumps should you do with the pump on the fuel line to avoid pumping.

I have also been told to do the "Needle Valve Adjustment" I have looked in the book. It says to remove the "knob" from the low-speed needle. Then to adjust the needle and then put the knob back on so it is center. But I can not figure out how to adjust the needle without the knon. There is nothing sticking out. Do you have to remove things from inside the head to get at the needle?
Thanks again
Donnie

 

[Nanich]

Re: 7.5 Johnson 1980 J8RCSS

I am still having troubles. Please help me!

I go down to the boat and the motor starts within a few pulls. It stalls and then it will not start again. If I pull the plugs they are all wet with gas. This tells me it is flooded. I dry the plugs, give the motor a few pulls to clean the air out and then put the plugs back in. Sometimes I get a sputter when I try to start it again, but after a few pulls nothing happens.

I tried the following things but I am still having troubles.

1. I turned the lean/rich needle all the way to lean, and then turned it to rich one full turn. This seemed to work and I got the motor started for a few minutes. When it stalled, again I got a few sputters when I tried to start it, but after a while I got nothing. I did notice a few things: The plugs where not wet, but when I tried to start it again I had air come out of the exhaust more often. (Is that a misfire/backfire)

I looked in the book about adjusting the SLOW ADJUSTMENT NEEDLE, but it talks about useing a TACHNOMETER (sp) I do not have one. Is there a recommended number of turns from MAX LEAN that you should try it at? I was messing with it around 1 TURN to 1 3/4 turns.

Any help would be great. I NEED IT!

Donnie