1975 15 hp johnson leaking gas on its side

[Johnson209]

Re: 1975 15 hp johnson leaking gas on its side

Fix it right! If it's blowing fuel out, it's running lean on that cylinder, which can cause piston scuffing and eventually a blown motor. Won't take you but a day or a few evenings to get it apart and seal it up. Then you won't have to worry about it...

I've aready order me some marine tex.
I'll see how it goes. If it still spits fuel then I"ll def have to take it apart

 

[Johnson209]

Re: 1975 15 hp johnson leaking gas on its side

I've aready order me some marine tex.
I'll see how it goes. If it still spits fuel then I"ll def have to take it apart

Hey fellows, is there anyway to test and see if my motors running on one cylinder or two. I recently did a quick test but not sure if im doing it correctly. When I pull the spark plug wires from the top cylinders my engine would still run. It will also start with the top plug unplug. When I did it to the bottom plug the engine dies and won't start. Any ideas?

 

[Xcusme]

Re: 1975 15 hp johnson leaking gas on its side

Hmm..from what you describe ,,,, the motor IS running on one cylinder only....the bottom one.

 

[OptsyEagle]

Re: 1975 15 hp johnson leaking gas on its side

That's the test. The top cylinder is not running or is weak.

 

[GA_Boater]

Re: 1975 15 hp johnson leaking gas on its side

It also appears the top cylinder is the leaking one too. I hate to say it, but patching isn't going to last very long. Have you checked compression? If you are in the States you can rent tools at Auto Zone for free. You buy it and return for a full refund = free. Flywheel pullers, compression gauges, etc.

 

[Johnson209]

Re: 1975 15 hp johnson leaking gas on its side

It also appears the top cylinder is the leaking one too. I hate to say it, but patching isn't going to last very long. Have you checked compression? If you are in the States you can rent tools at Auto Zone for free. You buy it and return for a full refund = free. Flywheel pullers, compression gauges, etc.

The motor ran good and strong the last time i had it in the lake this past month. Now that I've rebuild the carb and found a leak im thinking i shouldve just left it alone and not clean my carb at all becuase it was running fine the first place. I'll do a compression test tommorow and see we're I'm at. I'm hoping my marine tex gets to me by This week so I can see if it works. If I have to , I'll use jb weld on top of the marine texkidding
I post up the compression # tommorow
Thks guys

 

[Johnson209]

Re: 1975 15 hp johnson leaking gas on its side

heres my numbers for the compression test. 110 On bottom plug and 100 on top. Any ideas why its running on one cylinder?
Is there any way to check and see if my top coils are bad or weak?

 

[GA_Boater]

Re: 1975 15 hp johnson leaking gas on its side

For one thing that leaky joint is also sucking air into the crankcase instead of the fuel mix. After the motor runs is the top plug wet with fuel? Don't go chasing other things until the joint is sealed properly.

 

[OptsyEagle]

Re: 1975 15 hp johnson leaking gas on its side

heres my numbers for the compression test. 115 On bottom plug and 110 on topView attachment 182621View attachment 182622. Any ideas why its running on one cylinder?
Is there any way to check and see if my top coils are bad or weak?

Are you kidding? You have a crankcase leak. which you already observed when you made your video.

Obviously from your spark plug boot pull test, that leak is in the top cylinder. Since it is the crankcase that is leaking and compression is measured in the combustion chamber, it will have no effect on your compression numbers. That is why your compression numbers are pretty good, but that doesn't change the fact that your top cylinder is not going to work right.

That crankcase needs to be sealed. You see, your 2 stroke motor works like this. On the upstroke it pulls fuel in from your carb. That fuel has already been properly mixed for the perfect fuel to air ratio for combustion. In your motor, not only will fuel come in from the carb, but more air will come in from the leak, messing up your fuel mixture and possibly making it non-combustable. But you are not done yet. On the downstroke, your leaf plates should close, forcing the fuel up into the combustion chamber, however in your case a lot of it is pushed out that leak, as you observed in the video.

That has to be fixed.

 

[Johnson209]

Re: 1975 15 hp johnson leaking gas on its side

Yea u are right, i have to get the leak fix first. I just wanted to check my compression to have a good idea were I'm at since it was leaking.
Thks
I post up how the marine tex goes

 

[Johnson209]

Re: 1975 15 hp johnson leaking gas on its side

The top plug does get wet with fuel.

 

[Johnson209]

Re: 1975 15 hp johnson leaking gas on its side

So here's the progress. She's alive.
Got the leak seal with marine tex, hope it holds. I found another leak while sealing my leak n fix that with a new gasket. Also when I was cleaning my carb I remember Ive forgotten to add a little bit silicon on the aluminum plug that I took off to clean inside my ports. I think that was one of my problem cause the motor was running good before I had the carb cleaned. Well it starts good and idles better now. Gonna take her out testing this sat n see how she goes. Thks for all the help guys. The info I received has been very valuable to me and I appreciate everybody's comment n input.

Happy boating n stay safe..

 

[dazk14]

Re: 1975 15 hp johnson leaking gas on its side

Post a pic (a good one) of the Marine Tex patch. Did you remove ALL traces of paint, give the aluminum some "tooth" and degrease (acetone/lacquer?

 

[OptsyEagle]

Re: 1975 15 hp johnson leaking gas on its side

You should check if both cylinders are firing now, although if she pins you to your seat when you open up the throttle, that is as good of test as any.

 

[Johnson209]

Re: 1975 15 hp johnson leaking gas on its side

You should check if both cylinders are firing now, although if she pins you to your seat when you open up the throttle, that is as good of test as any.

Yea I redid the boot test. Took off each boot and now the motor does not die. I just haven't tested on the water just yet.
I post more info and pics after I get it on the water.

 

[Johnson209]

Re: 1975 15 hp johnson leaking gas on its side

Post a pic (a good one) of the Marine Tex patch. Did you remove ALL traces of paint, give the aluminum some "tooth" and degrease (acetone/lacquer?

Yeap I did that. I Sand it and prep it until all the paint was off and Recleaned it with lacquer thinner until it was shining.

 

[dazk14]

Re: 1975 15 hp johnson leaking gas on its side

Yeap I did that. I Sand it and prep it until all the paint was off and Recleaned it with lacquer thinner until it was shining.

Sounds Ok. Next time add "tooth", (read scratches), no shine, although we may be talking semantics here. Marine Tex does stick like crazy. Where is the pic for future readers... and of course, follow up.

 

[Johnson209]

Re: 1975 15 hp johnson leaking gas on its side

You should check if both cylinders are firing now, although if she pins you to your seat when you open up the throttle, that is as good of test as any.

Hey OpstyEagle, so I took out my motor for a test run today and it died out on me. It ran fine at 20 mph for approximately 2 or three miles down river. On my way back coming up stream it bog n died out. The motor had done this to me before but now its gotten worst. I couldn't get the motor to start for 5 minutes or so. Once it started, all I could do was slowly troll my way back cause it would died if i had it at full throttle. After crawling back for 20 minutes or so it would pick up again and run fine at full throttle. There's no more air leaking cause Ive check that. I'm scratching my head here. Any ideas what's causing this? Maybe a weak coil? It starts and i can troll fine the whole day.

 

[OptsyEagle]

Re: 1975 15 hp johnson leaking gas on its side

Running for a couple minutes and then dying and not wanting to start again is a classic symptom of bad fuel pumping. The quickest test is to try and squeeze the primer bulb when this happens and if it revives, you know that was your problem. It doesn't always mean you have a bad fuel pump, it can be bad gas tank venting (was the vent open), bad fuel hose, air leaks in the fuel lines and of course a bad fuel pump. Those are the easiest to check and if fuel deliviery is still a problem after they check out OK, then it is most likely a stuck carburetor inlet valve.

The loss of power is a classic symptom of only running on one cylinder. You should do your spark plug boot pull test for this. If it is only running on one cylinder, try and switch the plug boots and the clips and do the test again and see if the problem moves to the other cylinder. This will isolate if it is an ignition problem (coils and points and condensers) or a mechanical problem (crankcase leaks, compression, water in cylinder,etc).

It almost sounds to me that perhaps you had two problems happening simultaneously. Perhaps your old friend, the crankcase leak has come bad to haunt you and kill your top cylinder ...and... you had a fuel delivery problem as well.

Anyway, I would focus on verifying how many of your cylinders are rinning, for now.

 

[Johnson209]

Re: 1975 15 hp johnson leaking gas on its side

Anyway, I would focus on verifying how many of your cylinders are rinning, for now.[/QUOTE]


Thks again for the info optsyeagle . I did tried primering the bulb when it was dieing but that didn't help. I had to let the motor sit for a bit in order for the motor to start again. I also Check the fuel tank for leaks and it checks out ok. I'm going to replace the fuel tank line with a clear one and see what's happening if that's the corporate. What's wierd is It only does this when the motor is hot. It also seems like I have a prop slippage also. It would slip once or twice but that I don't think would kill the engine, I hope.
Anyways I'm gonna put it in the barrel today n see what's happening and go through the check list u gave me. Thks again I'll keep u updated.