Excess oil collecting in lower cowl and test tank - 1966 Johnson 6HP

[NicoPags]

I've had this motor for 2 weeks and first week was running great at WOT, not too great at idle.

Motor had come with original metal fuel tank full of last years gas. I dug out a newer plastic tank and put in fresh 50:1. with TC-W3.

Cold start took about 5 pulls and after I got out of the marina the motor bogged down when i went wide open. I played around and opened the choke and closed again and it sorted out and back in business.

5th time out, took 5 pulls again to start and repeated issue with the bogging down, played with the choke again but it did not sort out this time. If i pushed the choke lever 1/2 between open and close the motor ran alright but not at max rpm. Did some more fishing and determined at that point time to do a carb rebuild.

Today I finished up a carb rebuild. Motor starts on 2nd pull. threaded the idle adjustment screw all the way in and 1 1/2 turn back towards lean. Motor idled best when almost all the way turned to rich. The motor was most definitely idling much better than Ive seen before but thats when the oil and smoke started as well.

I'm getting 70psi top and bottom from cold start on 4 pulls, spark easily jumps up to 1/4 on both top and bottom could see it in the light of day too.

When I did the compression test, the plugs did have some oily carbon/buildup.

Based on how the oil collects on the pan under the plugs, am I heading towards a head gasket issue?

Also, I did some research on the motor online and resources pointed to mixing 50:1. The stickers on the OEM fuel tank say to mix 25:1

Any thoughts to what the excess oil cause is?

 

[racerone]

Fact----You need another 6" of water in your test bucket.-----Gasket between engine and exhaust housing may be leaking that oil.

 

[Crosbyman]

have you at least torqued the head bolts to spec ?? in any event pulling the cyl head is not a big issue… may as well get a
new gasket and resurface the cyl head dead flat

 

[racerone]

Check that wee hose ( oil recirculation ) on the side of the block as it may be cracked leaking too.-----The 1964 and newer models all ran on 50:1-----Your fuel tank may be from a 1962 model year.-----If the head gasket is original you may consider removing it.-----It would allow you to inspect cylinders to get an idea of motor use / wear.----And install a new improved head gasket with metal rings on the cylinders.----Sierra is the cheaper option.

 

[NicoPags]

Thanks Racer and Crosby. I just went out now and cracked lose the head bolts. Ill add some pictures as I go. I think ill sleep better doing a gasket change throughout anyway. I went out and took a snap of the oil return hose, maybe 3/4 to 1" if oil at the base but mostly its bone dry. I took the thermostat cap off out of interest and found no gasket at all there, and completely gummed up inside as well. Almost like a fiber like substance. Could be those airborne dandelion seeds that like to gather/pool in the rivers and lake. Yesterday when I rebuilt the carb, it had what I think was the original float in it, Cork like material? Going forward I am assuming everything is original.

 

[NicoPags]

Here are some pictures after the tear down. Cylinder walls are shiny and clean. Bottom cylinder had gas come out after pulling the head cover. Looks like some extreme oily carbon buildup on top cylinder, inside exhaust housing, and at the power head base. Apparently our local boat center no longer deals Johnson/Evinrude. shop.evinrude years cuts off at 1968 so called other nearest local dealer and they have some gaskets. What would be the best cleaning agent to start with to clean this all out?

 

[oldboat1]

Today I finished up a carb rebuild. Motor starts on 2nd pull. threaded the idle adjustment screw all the way in and 1 1/2 turn back towards lean. Motor idled best when almost all the way turned to rich. The motor was most definitely idling much better than Ive seen before but thats when the oil and smoke started as well.

Clockwise is lean (more air, less fuel), counterclockwise is rich. You seem to be adjusting correctly (actually getting a lean setting). Final setting is likely to be about 1 turn counterclockwise from lightly seated, but can vary.

 

[racerone]

First picture in post #6 picture tells me the motor needs to come apart for inspection.----Scored cylinder / piston and other issues !

 

[NicoPags]

First picture in post #6 picture tells me the motor needs to come apart for inspection.----Scored cylinder / piston and other issues !

:facepalm:

Always wanted to learn how to fully rebuild an OB

 

[racerone]

You have the power head off now so carry on.-----May not be easy to find new piston rings and bearing kits but you can always ask if anybody has some.