1996 Evinrude E25REDA Runs Fine Until Warm

[LukeFishWalker]

Yesterday I took the boat out and was shocked when the motor (Which was running fine) all of a sudden
started a consistent miss. I launched, got out of the wake zone and sped up and it went about 100 yards
and started to miss. I'd idle it down and it idles fine.

Today, I put the drum under the motor and cranked it.
It would miss consistently and idle fine.
I could see fuel coming out the high speed jet into the throat = Not fuel related.
I changed the plugs and I cranked it and it would run fine.
Took it to the river and launched, I got about the same distance as the day before and it started missing
again. Yes, I put the correct plug (Champion L77JC4). My guess is that a plug is fouled.

Any ideas as to why this is happening?
I'm about to barn this thing. Not burn....Barn = Put it up and forget about it.

I picked up a 1992 Tohatsu 25 yesterday which has low hours and looks brand new for $500.00
If I can't solve this mystery, you can bet the Tohatsu will be on this hull tomorrow.
As much as I hate to be labeled as a traitor, I will run the Tohatsu.

Thanks in advance,
Lukus

 

[LukeFishWalker]

Just to add more info, I am using the Tohatsu Synthetic 2 cycle oil.
The local Evinrude shop told me it was the same as or better than the OMC TC3.
Was that a lie to get me to buy the gallon of Tohatsu Oil?
The plugs are black, wet and sticky when I pulled them too.
Tomorrow I will pull them (To Frustrated Today) and check for white spark.

Thanks,
Lukus

 

[boobie]

Sounds like an ignition problem in the evinrude. Check your spark. It should jump a 7/16" open air gap on a tester. If it doesn't go to cdielectronics.com

 

[LukeFishWalker]

Is it possible that heat is causing the possible ignition issues?
This engine sat on a boat left in the weather for 8 years prior to me taking it off.
After cleaning the carb out, I started it in a drum and noticed the tattle tail wasn't peeing.
I shut it down, and ran the hose back through the tattle tail hole and all sorts of crudd
came out the exhaust in the mid section. Which of course I removed the exhaust cover
and cleaned it the best I could at the time.

I pulled the plugs today, cleaned them and it starts and rev's up fine.....But, the cylinder head
is hot to the touch. I read somewhere here at iboats that the cylinder head should remain
somewhat touchable. No, I don't have an infrared temp gun. But, I can tell you the head gets
hotter than the 2 second test and I have a pretty dang high tolerance for heat/pain.

I had changed the fitting on the tattle tail to a 5/16. Does this change the flow of cooling?
Does this allow the water to seek the path of least resistance and not flow through the
cylinder head cooling ports?

My next step will likely be to pull the cylinder head cover to exposed the thermostat, pull the
lower unit and flush the cooling system as best I can. Any recommendations of what to use
besides straight water from the hose?

Thanks, Lukus