96 Johnson 115 rebuild

[Tebassco]

Having rebuilt this engine 5 times (different block this time) i'm told to check timing after breakin 10 hours. Told to run across lake while doing so. How do i adjust it. thanks!

 

[Dhadley]

Re: 96 Johnson 115 rebuild

First, welcome!!<br /><br />Second, STOP!!!<br /><br />If youve rebuilt this engine 5 times we need to find and correct the cause of the problem. Tell us more about what goes wrong and the set up. <br /><br />Which 1996 115 is it? Crossflow or looper?

 

[R.Johnson]

Re: 96 Johnson 115 rebuild

After 5 rebuilds on one engine, I would take a long, hard look at something! What is the reason for these failures? Can you give us more information about this.

 

[Tebassco]

Re: 96 Johnson 115 rebuild

It lasted 4 years after an edjicated guess that is was intermittent VRO. It was unhooked and ran premix. It was rebuilt last fall after meltdown and only lasted a few minutes at full throttle after breakin. Nothing could be found wrong by anyone. Company doing the work decided it had overheated for some yet unone reason. I have installed a temp gauge and water pressure gauge. It seems ok so far but have not opened it up yet. So when i do i want to check timing...

 

[reeldutch]

Re: 96 Johnson 115 rebuild

did you have a meltdown running on 50:1 ?<br />are you shore the vro didnt use any oil out of the vrotank or did it?

 

[Dhadley]

Re: 96 Johnson 115 rebuild

First of all the company doing the work should check the timing. Not the customer. The next thing is that it does not have a VRO. It has / had an oil injection pump. Premix is still OK.<br /><br />Describe "meltdown". And since it only lasted a few minutes after the last rebuild, describe what happened. What did the pistons look like?<br /><br />There is a reason for everything. We just have to find it. Most likely the actual cause of the problem is being transfered from one block to the next.<br /><br />Again, is this a looper or a crossflow 115? The model number will tell all.

 

[R.Johnson]

Re: 96 Johnson 115 rebuild

Check timing before uou even start it up. You have me lost here. Do I have this right? It went "BANG" three times, run four years on pre-mix, went "BANG" again, run a matter of minutes after break-in, another melt-down. Are you now heading for 6, out of 6. That thing belongs in a jar of alcohol in a museum.

 

[Tebassco]

Re: 96 Johnson 115 rebuild

Yes, it has a VRO. I just put a new one on it. It is a bubble back cross flow. Timing advance is what i meant to say.

 

[Dhadley]

Re: 96 Johnson 115 rebuild

A crossflow. OK. A very simple motor. 1950 technology. Describe what happens. Is there a hole burned in the center of the piston? Top edged gone by the exhaust port? Scuffed? Rings broke?<br /><br />What was the timing set at before? How was it set? What fuel? Oil? Spark plugs?<br /><br />BTW -- you dont have a VRO system. You have an oil injection system.

 

[Tebassco]

Re: 96 Johnson 115 rebuild

Well...i have 2 manuals that show it and i paid $360 for a new one...? Most of the scoring was around the exhaust ports...

 

[Dhadley]

Re: 96 Johnson 115 rebuild

What was the timing set at before? How was it set? What fuel? Oil? Spark plugs?<br />

If you have a manual that says the motor has a VRO system, its probably the wrong manual. That new of a motor never used a VRO, it was a (somewhat) constant ratio fuel/oil pump.<br /><br />We need a better discription of what happens to the pistons. You say the area around the exhaust port is scuffed the worst. What about the dome of the piston?

 

[Tebassco]

Re: 96 Johnson 115 rebuild

Never any problem with the dome. Time before last it broke a ring...

 

[OBJ]

Re: 96 Johnson 115 rebuild

Just a thought.....do you know if the edges of the ports where chamfered after boring/honing? The sharp edges left by boring/honing can catch a ring real easy.<br /><br />You can feel the edges easy with your finger and can tell if its been chamfered.

 

[Tebassco]

Re: 96 Johnson 115 rebuild

It ran for 4 years before dropping the ring..