QD-10 that runs horrible. Expert advice needed.

[huntleybill]

I picked up this QD-10 last weekend and ran it in my test tank. Low RPM’s are ok (not great) but I can’t seem to get it to run well at high speed. I have attached a video for your viewing pleasure.

This is what I have done so far:
Cleaned and adjusted the points. Spark is blue and strong. Easily jumps a 1/4".
Adjusted plug gap to .025. I did not replace the plugs as I ran out. Plugs seem "newer".
Dis-assembled and cleaned carb. fuel lines, fuel filter.
Compression tested at 75 and 70 psi.
Adjusted idle speed needle until motor ran the best (that is where is is set now).
Adjusted high speed needle in 1/4 increments until needle is closed with little to no results/improvement.
Cleaned carb again, same results.

Are there specific troubleshooting steps to narrow down the causes in these situations. I’m told most carb problems are ignition but it seems that the ignition is working fine. Can’t be head gasket or head as the compression is even (albeit seems a little low to me but what do I know).

Video shows motor shaking sputtering. Fuel mixture is 24:1. Gas and oil is fresh.

How can I get this motor running as good as it should?
Thank you for your advice.
Bill

https://youtu.be/eDIXRmN5_kQ

[frankr]

That is one of those motors that could be slowed down by lifting the tiller. But they ran rough when you did that. So my question for you is, is the carb throttle butterfly opening?

[huntleybill]

hmmm…I don’t recall even looking at that. So I looked, and yes, it is opening and closing.

[retiredoz]

That cam follower is really supposed to follow that cam. It’s backwards from ‘normal’ operation, pushing it forward closes the butterfly..Push it by hand while you’re trying to run at high speed and see if that helps .The spring that operates it seems to not have enough poop.

[fisherman6]

When trying to run this motor in a test barrel, make sure the selector switch neat the base of the tiller handle is set to "OFF". That will prevent the tiller handle throttle control from affecting it’s running. That is a handy feature on a boat, but it can be a pain in a test tank, especially if you either don’t know about it or for get about it.
-Ben

OldJohnnyRude on YouTube

[huntleybill]

Thank you Ben. I will try your suggestion tomorrow and report the results.

[bob-d]

Huntleybill I have the same motor, and carb tuning is a pain. Cant get midrange to smooth out. Look up my posts from last week.
This won’t help your problem but I think the recommended oil ratio for this model is 16:1.
Bob D

[fisherman6]

The QDs were all 24:1 recommended mix ratio motors from 1949 thru 1963. 16:1 will not hurt any of them though.

These carbs are a bit more finicky than the 1954 and later ones and do not transition from low speed to high speed circuits as smoothly.
-Ben

OldJohnnyRude on YouTube

[bob-d]

Hey Ben, the 16:1 that I mentioned came from the owners manual with the 30W car oils.
Did they send out an update for the early QD’s with the better modern day oils?
Bob D

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[chris-p]

Pull the plugs after running, are they wet?

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