1950's Evinrude Fleetwin 7.5 HP Spark Plugs Leak Oil

[andy7918]

I have a 1950s vintage Evinrude Fleetwin with the pressurized fuel tank. The motor purrs on low speed, but on wide open it misfires intermittently. SO far I have rebuilt the carburetor, replaced coils and spark plugs with a J8C (tried a J6C too). After putting a few hours on the motor this weekend I noticed that both of the spark plugs are leaking oil between the threads and down the front of the cylinder head. Could this be the cause of my intermittent misfire? The plugs are tight, but I didn't use a torque wrench as I don't know the spec for this motor. There aren't many threads and I don't want to strip them out. Could someone tell me the torque spec, and has anyone seen a motor leak oil past the spark plug like that? Could that be the cause of my misfire (intermittent blowby past the plug)?

 

[Daviet]

Are the gaskets between the plugs and cylinder head installed?

 

[Tim Frank]

When was the last time the condensors were changed?

 

[andy7918]

The metal gaskets are still on the plugs. The condensers may have never been changed. They looked fine to me when I changed the coils, plus how could the condensers cause the motor to leak oil past the plugs? I pulled the plugs today and both were pretty black with oil. This motor specs a really rich mix 1/2 pint oil/gallon so I'm not too surprised the plugs are black. I will try to post some pictures of the leak and the plugs tonight.

 

[Vic.S]

The seals between the plug and the cylinder head are either defective, the seats in the head are damaged or the plugs are not tightened properly.

The correct torque is 25 to 30 Nm or 18 to 21.6 lb ft

http://www.championsparkplugs.com/learning-center/article/421/plug-torque-settings

 

[Tim Frank]

Edit : dreaded double post

 

[Tim Frank]

The condensers may have never been changed. They looked fine to me when I changed the coils, plus how could the condensers cause the motor to leak oil past the plugs?

Obviously the condensors are not going to cause an oil leak.

You originally complained about a misfire and were looking for the cause of that. Condensor(s) are one possibility.

But I guess you've sorted that out....so ignore my question about the condensors.

It also looks like you have another thread going about this same motor. You'll have better luck if you keep the problems grouped.
At this point you are all over the map.

 

[andy7918]

http://s113.photobucket.com/user/ANDY7918/library/Spark Plug This is a link to some photos. Tim, if both plugs are getting spark when I turn the flywheel by hand the condensers shouldn't be the problem right? Is there a way I can test them with a multimeter?

 

[Tim Frank]

You can test them....google "Leeroy's Ramblings"....i seem to remember that he has the procedure in there somewhere for testing.
I'll be honest, I've never tested condensors, They are cheap (LT $10-/pair) enough that if I don't know their history, I just R&R them. They aren't as rugged as coils.
The problem that I've had with them, that I know for certain was their fault, was when they warm up, they can cause misfiring and crappy running.

Have you verified good compression in that engine?

 

[andy7918]

No i haven't verified compression with a compression tester. I tightened down the plugs with a torque wrench to 20 ft/lbs and i will test it out this weekend.

 

[andy7918]

Tested it out with torqued down plugs today. Fixed the oil issue, but was still missing. I pulled the plug wires one at a time while the motor was running and it is misfiring on the top cylinder. THat is odd as when i check the spark by holding the individual plugs against the cyliner head, both fire.... I verified that both cylinders are getting fuel. I went ahead and ordered new condensors from the auto parts store at $7.00 a piece i am wishing i replaced them when i replaced the coils. Hopefully that solves my problem. I gapped and cleaned the points when i replaced the coils originally and checked that i had the same resistance value on both plug wires. Is there anything else i should be checking as far as the ignition system is concerned ? I did verfy the plug gap is within range as well.

 

[nwcove]

holding a plug against the block is basically a useless test for spark quality.....get yourself a $10 open air tester , adjust it to 1/4 " and see what you have. you should be able to hear it make a nice snap !

 

[Tim Frank]

If you go to the "Top Secret" files, there is a wealth of info and troubleshooting basics there.
You may get lucky and replace a defective part and solve the problem that you are having.....even a blind squirrel sometimes can find a nut.
But you are far better off and will have more $$$$ in your pocket if you follow the described systematic approach to troubleshooting.

You don't at this point really know definitively whether your compression values are OK, and you certainly haven't verified the ignition system, but have already spent more on parts than you would have on a compression tester, a spark tester, and a manual.

 

[andy7918]

So i ran a compression test on the motor, 75+psi on bottom cylinder and 70 psi on the top one thats misfiring. Checked spark with a spark tester, and bottom one is good to a .25 inch (nice snap too), top would only spark across after a few rotatation (sign of bad condensor?).Replacing condensors and back to test bucket.

 

[Tim Frank]

Your compression is "OK"...especially hand-pulled, cold.. Once you get it running regularly, those values may come up.
So you have an ignition issue....seemingly restricted to one cylinder.

The first thing I'd do now is recheck the connections of the high-voltage lead at the coil and at the plug boot. Easy to slip up on them once in a while.
The coil end twists onto the threaded post in the wire channel. At the boot end, make sure that you have a good contact between the wire core and the piercing "prong'.

After that, swap condensors from one cylinder to the other and see if the problem moves to the bottom cylinder. if not, recheck point gap and cleanliness.

 

[andy7918]

After I pulled the flywheel I found my problem. The grounding wire that is attached to the coil and bolted with the same stud that holds down the coil had been rubbing against the flywheel. It had rubbed so much that the insulation had worn off which must have been causing my intermittent miss. I fixed the wire, replaced condensors while I was in there and put it all back together. The threads are definetly damaged on the top spark plug hole. I am going to try to pick up a salvage cylinder head locally, ordered a new gasket kit yesterday.

 

[Tim Frank]

Gotta love the "...lived happily ever after endings... "

 

[andy7918]

So i ended up using a helicoil to repair my head which worked great. Replaced the head gasket with a new solid metal one. I have never seen a headgasket like that before... I ordered a clymer manual that is supposed to cover evinrude/johnson from 58 to 70s 1.5-125 hp havent recieved it yet. I know my motor is older than 58, but i doubt much changes. So i took the motor for a test run and it still misfires at wide open throttle, will never get up to full rpm before misfiring. What could the problem be? The motor runs great at idle and great up to about half throttle, and starts after like two pulls cold. I am hoping the repair manual will have the answer for things i could check, and hopefully there are some good schematics so i can see whats going on inside this motor without tearing it apart and i can also know that everthing is put back together correctly. I sprayed wd40 all over the intake/carburetor while the motor was at wide open hoping it would show an air leak as the wd40 temporarily plugged the leaking intake, but no difference. Any ideas on other things i can check? I am about ready to throw this thing away, but i am stubborn and want to figure it out.

 

[dazk14]

With all the oil your running and the pic of your plug so coked up and somewhat low compression, a good decarb is in order. Pronto. More compression always helps with firing.

Have you tried adjusting your high speed fuel mixture needle?

 

[andy7918]

So yeah I have played around with both of the needles a ton even after the motor was warmed up. I adjusted the high speed from flooding the motor to all the way closed and it's not the issue. I am thinking that it has to be something wrong with the armature/points/plug wires. (all of the stuff under the flywheel). The motor runs great on idle and up to half throttle, but maybe there is something binding up or pulling on the plug wires? My thought is to put throttle to full and check spark with my 1/2" spark tester again. I was also thinking I could take apart the tiller handle and see if there is some kind of kill switch for when you turn it to "stop". Though I am thinking this motor doesn't have one...