1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

[srollin]

Hi, I have the motor listed above and I noticed that after running it there's some fuel mixed with oil in the spark plug cavities. It seems to be simply coming out of the threads. It's not aot though, is there any kind of gasket or o-ring that is missing on the spark plugs?

Thank you!

Sebastien

 

[boobie]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

The only gasket you have is the one on the spark plug. Get a new set of plugs and torque them to the correct spec.

 

[F_R]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

Very good chance the threads have been stripped and somebody has repaired it with Heli-Coils. Nothing wrong with that, except they are very difficult to get straight if you do it by hand. If you don't get it straight, the plugs will go in at a slight angle and leak. Once they are done, they are done. No way to straighten them up except to replace the head or use a different type of repair insert.

 

[boobie]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

Can it be all three plugs were stripped ??

 

[srollin]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

The threads don't seem to have been redone or replaced, but I could be wrong. I know the previous owner changed the spark-plugs, but I'm not sure if he installed the proper ones. Is there such a thing as marine-grade spark plugs? I don't see any gasket on the spark-plugs so I should have a gasket between the spark plug base and the head of the motor. It would make sense, I just didn't know that they came with a gasket. Would it cause the motor to have issues with idling sometimes?

 

[halfmoa]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

My 1972 65hp Johnny 65ESL72S does the same thing. The washers don't look crushed and my wife's grandfather who bought the boat new assured me the plugs were never stripped. It's never been an issue outside of cosmetics.

Here's my very brief thread.

 

[retiredfornow]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

If the plugs were real loose, that would screw up the compression, making it run erratic.
Do what boobie said, get a new set of plugs and torque them in. "Most" plugs have a seal ring on them.

 

[F_R]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

All of the correct plugs have a gasket. Meaning somebody has put who-knows-what in there. There are such things as tapered seat plugs, but not meant for use in that motor.

 

[sludgeguy68]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

I had a similar issue on a 25hp of the same year. Threads were stripped on 1 hole - I think the plug actually popped out while running. I could see the little metal threads crumbling off the plug's grooves - this might be an indicator to look for. Looking at the threads in the hole with a flashlight, I could see they were kind of mashed-up looking, compared to the non-problematic hole. Heli-coil was the solution.

 

[durban]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

just a suggestion i would check the reed valve for that piston , what you may find is that on the top end of the reed valve where the plate that hold the reed valve down with 3 screws , i have found some dirt towards the top end , cant be seen looking through the carburetor intake on the manifold , u have to take it right out , the dirt in the top causes the reed valve not to function as it should , it gets in between the top of the reed valve & reed valve body , & therefore does not close as it should

 

[srollin]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

Thank you guys, I'll check it out and give update if it's not working.. Btw, it's an electric shift and the reverse gear doesn't seem to engage, it gives out a soft grinding noise like the gear pinions are barelly touching the drive shaft. Is there something I can do to try to fix it without opening the lower unit, is there a shift rod that is probably unajusted?

 

[F_R]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

Your motor has Hydro-Electric Shift. Altogether different than "Electric Shift" Hydro electric is shifted by hydraulic oil pressure. The electric part only activates a couple of oil flow control valves.

FIRST thing to do is check the oil in the lower unit. Is it full and no water in it? Is it the correct oil? Evinrude "Premium Blend", or generic "Type C".

Once you resolve that question, and it still doesn't shift, check the voltages at the blue and green wires by the powerhead. They go down to the lower unit. Slide the insulators back and check them with a multimeter, wires still connected. There should be battery voltage on the green wire with the neutral button pushed (key on). There should be voltage on BOTH the green and blue wires with the reverse button pushed. If it fails, there is an electrical problem, usually the push button switch is bad. ($$$$)

If it passes the voltage test, and still no shift, trouble is in the lower unit. ($$$$$$$)

BTW, avoid letting it grind. That is wearing the clutch dog and reverse gear, creating fine metal chips. The metal chips get into the piston in the oil pump, and it will never work again without tearing it down and cleaning the chips out. That may be the problem already.

 

[boobie]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

Maybe I can't see but, what ever happened with the leaky spark plug issue ??

 

[srollin]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

Hi guys,

I changed the spark plugs and on the top cylinder it seems like the threads are damaged, I don't know if they leak anymore since it now runs fine when it's on the water muffles, but under load on the lake it stalls. I tried to adjust the iddle adjustments on the carbs, but it barelly made a change. I did change the lower unit oil for genuine Evinrude premium oil so that is done. That motor will be the end of me I sware. The gas in the tank could need a change though. When I bought the boat last year, I didn't change the gas and I don't know how much time it was sitting in the tank I have put a stabilizer in it, but still.

Thank you for the tip on the shifter, I didn't have a chance to check if the reverse work better.

For the spark plug, is there a type of insert that would be best?

 

[srollin]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

I'm thinking of buying the Full Torque insert kit (fulltorque.com) as anyone tried it?

 

[boobie]

Re: 1973 Evinrude 65hp 65373S Fuel leak trough spark-plug holes

Edit.