Johnson J25 ELCTD keeps burning out top coil

[racerone]

A bad coil does no damage to a cylinder !!

 

[c-dubb]

A bad coil does no damage to a cylinder !!

I understand that this is two separate issues. This engine has a history of burning out the top coils. The top coil was bad this time as well, I then replaced the top coil and verified that it now has fire. It still would not crank so I tested compression and got 0 on the top and 100 on the bottom.

 

[F_R]

Makes me wonder if it is running hot. And that caused the head gasket to blow, in addition to melting the coils.

 

[c-dubb]

Makes me wonder if it is running hot. And that caused the head gasket to blow, in addition to melting the coils.

I was thinking about that too. It seemed to run hotter than normal about a year ago when the top coil was going out frequently, so i pulled the thermostat and replaced it. The old one was oxidized badly and wasn't working, but I did not have another coil go back out until now so maybe there is something to that. I will check the head gasket probably tomorrow and hope that is all it is. I haven't checked the impeller yet, but it was producing a strong, steady stream of "pee".

 

[racerone]

The " pee " stream does NOT MEAN that the motor is cooling properly !----See post # 2 on this.

 

[c-dubb]

Makes me wonder if it is running hot. And that caused the head gasket to blow, in addition to melting the coils.

Definitely Blown head gasket! It blew in the same area the coils are mounted, so maybe it was overheating coils the entire time...i’ll update the post when the repairs are completed, about to pull the lower unit now and check the cooling system.

 

[c-dubb]

OK, so the impeller and housing all look to be in good shape but I ordered a complete water pump repair kit anyway (housing and all) and I will be testing the thermostat for proper operation while it is torn apart. What else is there that is cooling system related that I should check?

 

[racerone]

Water diverters in the water jacket.-----They guide water around the block for proper cooling.

 

[c-dubb]

Water diverters in the water jacket.-----They guide water around the block for proper cooling.

Would that be the three rubber pieces (1 top, 2 bottom) between the cylinder walls and the block? If so, should they be replaced or just verify that they are there and not falling apart?

 

[c-dubb]

Update: Installed new water pump kit and head gasket. I now have 120 psi on both cylinders and it fires up immediately, hardly having to turn the key at all. It has never started and idled so good since I’ve had it. I’m not sure about the water flow from the tell tale now as I don’t have near the pressure coming out as I did with the old water pump, but it is still a steady stream. Should I pull the lower unit back off and look for obstructions in the cooling system or a mis-aligned supply tube?

 

[c-dubb]

It was losing pressure at the water pump housing. I reassembled everything and now it is pumping water like a boss and running better than it has since I have had it. Thanks for all the input!