1998 Johnson 115 j115tsxecm one cylinder not firing

[Muskiematt]

Hello, I have 1998 johnson 115 and I have a dead cylinder. After I took it out for a little ride I noticed it had little power under a load. When I got home I did a compression test and found that two cyclinders on one side of the v had 120psi and the other side had 100psi on top and 90psi on the bottom. The spark plug had no signs of firing on it and had some water on it when I removed it. So I think I have head gasket or water jacket gasket is leaking but I can't understand why it's not getting gas to make it fire. It def had strong spark to plug. Could it be not enough compression to open reed valve? Or maybe water is preventing the firing? I would think a little water wouldn't stop the firing process but I tell you the plug looked brand new with no oil or carbon on it. Any ideas? Thanks !

 

[Daviet]

Re: 1998 Johnson 115 j115tsxecm one cylinder not firing

Your engine will not run on water, repair the water leak.
You might also preform a spark check, it should jump a 7/16" air gap and be bright blue.

 

[HenryB]

Re: 1998 Johnson 115 j115tsxecm one cylinder not firing

Could be serious stuff. Water (and you have a lot; the clean plug attests to that) in the cylinder will rust the rings to the cyl wall, so get some oil in the cylinder pronto, and give it a regular spin to make sure no water is left in the rings. The head to cylinder joint sounds like it is shot. Remove the heads and pray that it is the head surface that's shot. The head can be machined for short money, but the cylinder joint is serious stuff.

 

[Muskiematt]

Re: 1998 Johnson 115 j115tsxecm one cylinder not firing

Hi thx for the replys. When you say joint do you mean the gasket . I think the plug remained new looking cause it was not getting gas at all.. Possible reed?

 

[HenryB]

Re: 1998 Johnson 115 j115tsxecm one cylinder not firing

No, I mean the head to cylinder metal mating surfaces. One or the other has a leak path. Water is bypassing the gasket and entering the ignition area. That is why the plug is clean.

Don’t wait to get oil into that cylinder, or you will have a devil of a time freeing the piston

 

[Muskiematt]

Re: 1998 Johnson 115 j115tsxecm one cylinder not firing

Ok thx for your reply ..

 

[Faztbullet]

Re: 1998 Johnson 115 j115tsxecm one cylinder not firing

That motor does not have head gaskets it has o-rings that rarely fail, I have only seen one that failed and motor has been extremely hot.. you need to look at other sources such as crankseal, glue line leak in block, or piston skirt broke and ding internal water jacket. If its a salt water motor the internal water passage could be eaten thru...

 

[Muskiematt]

Re: 1998 Johnson 115 j115tsxecm one cylinder not firing

They sell a head gasket and water jacket gasket for this motor.. Johnson evanrude website . Diagram shows gaskets

 

[boobie]

Re: 1998 Johnson 115 j115tsxecm one cylinder not firing

Fazt, it's a cross flow according to the model #.

 

[Muskiematt]

Re: 1998 Johnson 115 j115tsxecm one cylinder not firing

Can u find a diagram ?

 

[Muskiematt]

Re: 1998 Johnson 115 j115tsxecm one cylinder not firing

Do you guys think that 90psi of compression is enough to pull fuel though reed valve. When the others cylinders are much higher. That cylinder had NO fuel at all . Or do you guys think it's a two part prob.. Thoughts?

 

[Daviet]

Re: 1998 Johnson 115 j115tsxecm one cylinder not firing

That cylinder should fire with 90 psi compression, may not idle well, but it should fire.
The reason the plug looks so clean is that it is being washed clean by the water, you need to fix that problem as soon as you can to prevent the cylinder from rusting.