qd 10 oil ratio

[steve001hsd]

I have been working on my seahorse for about a week or so. It runs good for a few and then bogs down in the barrel. i pulled the plugs and i see oil coating the plug electrodes. I am mixing at the recommended ratio of 1 qt to 4 gal of fuel. Is there any chance I am mixing too rich on oil? I am using 2 stroke oil instead of 30 weight. The motor seams to sputter erratically and then die. Does not matter if I’m in neutral or forward. I would think I’m mixing too rich but again but I am flowing the ratio on the motor cover. Any input is appreciated thanks.

[steve001hsd]

Also i get what i would call too much smoke if this was a dirt bike or any other modern engine but I’m not sure.

[Mumbles]

Due to its age the compression might be too low to burn off the oil completely. Try running a hotter plug if this is the problem.

[chris-p]

What year/model are you working on?

As stated, step 1 test compression.

Step 2, will the spark jump a 1/4" gap on a tester with a bright blue ZAP!!?

If you have good compression (about 70 to 100 psi on the QDS), and good spark. Open the carb up and clean/rebuild.

Having it smoke a lot in a barrel is very normal. Will not be as bad on open water.

[frankr]

quote steve001hsd:

I have been working on my seahorse for about a week or so. It runs good for a few and then bogs down in the barrel. i pulled the plugs and i see oil coating the plug electrodes. I am mixing at the recommended ratio of 1 qt to 4 gal of fuel. Is there any chance I am mixing too rich on oil? I am using 2 stroke oil instead of 30 weight. The motor seams to sputter erratically and then die. Does not matter if I’m in neutral or forward. I would think I’m mixing too rich but again but I am flowing the ratio on the motor cover. Any input is appreciated thanks.

You will get all kinds of opinions on the oil question. All I say is that the QD motors are notorious for beating the wrist pins loose in the pistons. If it were mine, I wouldn’t skimp on the oil. It probably will still beat the wrist pins out, but maybe take longer.

Again, opinions, but I say use today’s TCW-3 outboard oil. That old car oil carboned up motors and piston rings something terrible. TCW is TCW because it has been tested and proved to not do that so badly.

[steve001hsd]

Ok I found one of the points was grounded. I fixed this issue and now have fair spark on both plugs. I don’t get bright blue but rather an orange spark. So I would guess the coils are a little week. This is a 49 with original coils so I’m not disappointed. The coils and condensers test out with a meter. I pulled the carb again and checked all the passages with pipe cleaners and compressed air. It looks good and after making a few new gaskets and sealing the float for good measure I reassembled everything. What is the best way to check and set the float on thus carb. Also the compression is at 70 psi on both cylinders.

[steve001hsd]

Also I tried using the champion j6j plugs that it came with as well as autolite equivalent. What is the correct plug for this engine? To reiterate this is a 1949 johnson qd 10. 10 hp twin. If the plugs are too cold what is recommended for a hotter plug? Would the j11j or equivalent be too hot?

[jerry-ahrens]

I’d have to look, but I believe J6J is correct. J6C is the modern replacement. That engine should jump a 1/4 inch air gap while testing the ignition. How about the high speed needle adjustment? It sounds to me like it’s open to far… Try 1/2 to 3/4 open from a gently closed position. Low speed should be set 3/4 to 1 turn open from a gently seated position. It’s about impossible to get the high speed jet properly set in a barrel. You can get it in the ball park maybe, but it needs to be on a boat to properly adjust.

[steve001hsd]

Ok sound good. I’ll work on the jet adjust after work today.
I was not sure on the baseline but I was adjusting "by ear" much like I do my truck or my Harley. FYI both are older 80′ carb models as well. I must like punishing myself lol.

[beerman57]

Don’t forget, sometimes a motor will choke on it’s own exhaust when running in a barrel. Try setting up a fan to blow the exhaust away. My QD11 only has 70psi and runs like a champ.
Original coils are OK? Man, I would like to see 67 year old coils that are still good!

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