65 hp Johnson 1968 Vintage

[jimmehoffa]

so its the dead of winter in Minnesota and I am thinking about my boat..

I have a 1968 or 69 65 hp Johnson VXL 4 cylinder outboard on my 1968 Glassbar Avalon. The motor generally runs OK ...if... it has a fresh set of plugs, preferably Splitfires.
I need to change the plugs out at least every 20-30 hours of running. It starts good, has good high speed power, but marginal low speed operation.
It will misfire, stumble and foul out the plugs.
I have worked on the carbs, quickie cleanup and rebuild with gaskets.

I am considering tearing into it this winter. What would need attention after 40 years of duty? (I doubt that the motor has had 600 hours of use in its life)
It has never been apart.
thanks

 

[jasper60103]

Re: 65 hp Johnson 1968 Vintage

Hi, Jim.
Lot of us minnesotans like to hang out here and dream of spring. Some of the pros will chime in soon.

They will probably recommend getting a factory service manual. If you don't have one, Ebay is your friend. $9.99 is a good deal. http://cgi.ebay.com/ebaymotors/1968...1QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247

 

[James R]

Re: 65 hp Johnson 1968 Vintage

Looks like a nice rig.
Having a manual on your motor is the best way to go
First thing do a compression test. With out that you can waste your time and money.
All cylinders should be even within 10%. If not it could be just a sticking ring or it might be a scored bore. Try shooting marvel mystery oil down the plug hole and turn it over a few times. Leave it to soak overnight. If you have a good improvement in compression on the bad one then it could be just a stuck ring.
Yamaha ring free will probably put that right when you run the motor.
A proper cleaning job on the carbs is a must.
Setting the syncronization of the carbs and the timing advance must be done by the book. Dont try to guess this, it wont work.
Replace the pump impeller and drain the lower unit oil. Where you are the oil wont run if outside. Got to be warm. Check the oil for metal particles and water. If the oil is milky water has got in. Will need new seals at least. After all this the motor will need running and warming up and the carbs set up and the syncronization re-checked.
Give it a dose of Sea Foam to clear the carbon deposits and all should be well.
Good luck.

 

[steelespike]

Re: 65 hp Johnson 1968 Vintage

It appears the 65 was a one year wonder 68.I don't have info specific to the 68 my info only includes up to 67. and 69 to 89.It may use either a belt driven distributor magneto or a belt driven battery ignition distributor.I'm pretty sure ignition parts are hard to come by and expensive.I would start with a manual then the compression test and a spark test using a spark tester available at an auto supply.After all these years I'll bet the distributor belt is probably not tight enough.And timing may need to be set.
If it doesn't have a distributor then I've wasted your time.
It will have a capacitor discharge ignition.using a different distributor.Be careful to use proper procedures to avoid damage to the ignition.I would suspect the fuel system for your constant fouling of plugs.May need a carb rebuild.Many outboards have fouling problems if the fuel pump has a hole in the diaphram.But not likely to foul all plugs.Do the plugs appear evenly colored and what color are they?
The split fires are a gimick and not likely to be making any difference.
The 67 motors use a Champion J4C plug ,used to be J4J.I'm assuming the 68 is the same.If your Splitfires are too cold it could be causing premature fouling.

 

[F_R]

Re: 65 hp Johnson 1968 Vintage

The 1968 has battery Motorola CD ignition with an under-flywheel distributor. Therein lies your problem. That was a marginal ignition system at best. The spark "gets lost" as it goes through the distributor. There are also two sets of breaker points in there and an anti-reverse cut-out ring. Clean all that stuff up and set the points to exactly .010". Lubricate the anti-reverse ring very sparingly with EP grease. Make sure all electrical connections are clean and tight, especially the battery cables.

Toss all those funny spark plugs and install Champion L77JC4 or QL77JC4. Those were lifesavers on those systems.

If everything is right, it will run well. If not right, you will get a head full of grey hair...like I did.

 

[jimmehoffa]

Re: 65 hp Johnson 1968 Vintage

I have done most of the things suggested
oil gets changes every year before storage
Sea-foam thru the carb to burn off carbon (did not seem to make a diff)
Sea foam in the fuel all the time.
The ignition was replaced a couple of years back, it is the CD ignition, however I bet the plug wires are original (solid core wires)
Compression was good and the same on all 4 cylinders the last time I checked it.
I do have a manual.
I have used Champion plugs in the past (Ql77JC4) but they did not even last one season. they were black and oil fouled very quickly. the Splitfires last at least 2 seasons. (SM264D)
What I was wondering about is (valves) reed valves? Is that a maintainence item?
For sure I need to tear into the carbs again, as all I have replaced in the past were gaskets. What else can be replaced? needles seats? Is there a complete carb rebuild kit available? where?

thanks for the help.

 

[steelespike]

Re: 65 hp Johnson 1968 Vintage

How about the crankcase bleeder valves.designed to remove any excess fuel or oil from the crankcase.Like little reed valves one for each pair of cylinders.
Mounted in intake block.
This info comes from my 67 intake exploded drawing.So may be different on the 68 but still should be bleeder valves of some sort.One side effect of bad bleeder valves is plug fouling.