QD16 tuning

[Rob]

Hello everyone,

 

I am a bit of newbie here, and I’d appreciate the advice with a problem I am having from those who are far more experienced than I am.

I recently finished a tune up on a QD16 10hp. I went through the magneto and replaced the coils, points and condensers. I used a ring and pointer that I bought years ago, possibly from someone on here, to set the coil gap and timing.

I also cleaned the carb.  I did not replace the water pump, but it is pumping water pretty well.

I am trying to tune it and would appreciate some advice. Here’s the problems I’m having:

It is a little hard to start; it takes a bunch of pulls and almost 3/4 throttle advance.  Once I got it started, I adjusted the high and low speed needles until it stopped sneezing. After I got it to stop lean-sneezing, I found that it doesn’t seem to want to idle down very slow no matter how I adjust the needles. It also seems kinda sluggish when I advance the throttle.

One thing that I did notice while I was adjusting the brass throttle advance on the magneto, is that someone before me has wrapped the throttle roller in duct tape. Even with the brass throttle advance pushed all the way towards the magneto, the plate will start advancing the throttle way before the roller gets to the marks on the magneto. I assume this is making it run rich and fast (preventing a low idle speed), is that correct? I know the obvious thing to do is to replace the roller with one that hasn’t been wrapped in duct tape, but before I go overpaying for a worn out, used one on Ebay, I wanted to confirm with the experts on here that the little roller can cause this kind of problem (hard starting, sluggish throttle response).

I know that’s a bit of a loaded question because there’s a bunch of things that could cause this (low compression, poor timing adjustment, poor carb adjustment, etc) so if you have any other ideas about tuning, please throw them out!

Thank you all for your time!

 

Rob

Rob

[frankr]

Well yes, that could be a problem, as you suspect.  In any case, it will have to be corrected before you can get it to run right.

PS, you probably got the tools from me.

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Rob

[labrador-guy]

Rob you can repair those rollers pretty easy with some shrink wrap.  The kind you would use on electric wiring.

dale

 

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Rob

[crosbyman]

if the roller gouged you can always  fill in the gouge with  JB expoy then heat shrink wrap  it  has suggested

Joining AOMCI has priviledges 🙂

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Rob

[Bob Wight]

As Frank noted, you’ll have to fix the cam roller as the first step to get the carb/throttle sync correct, then go from there to see what else might be causing a problem.  And as Dale and crosbyman noted, the worn roller can be fixed with heat shrink tubing.   On a recent project, I had a cam roller that was so badly worn it was useless.   While browsing in my local hardware store, I happened to find a hard nylon spacer that was a perfect substitution for the original piece.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

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Rob

[crosbyman]

great suggestion bobw…

or make up a roller with anything round (metal rods,  bolts etc… cut to the proper lenght and drilled out to fit.

 

these clips work great also to act as a roller retainer if need be .. they come in all sizes and  don’t let go !

 

I used them to fix  a choke linkage on a 9.5hp

Joining AOMCI has priviledges 🙂

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Rob

[Rob]

Thanks everyone!!

I pulled the roller off and removed all that silly duct tape. Turns out, it wasn’t in as bad of a shape as it looked from my previous observation. Once I pulled the tape off, the actual roller was in pretty decent condition. So I cleaned it off and put it back on.

Then I adjusted the brass throttle cam until the throttle was just starting to crack open when the roller was in the center of the marks on the magneto. I am going to have to wait until it warms up outside a bit before I can try to run it in my trash can, but I am sure it’s going to be MUCH better.

Thanks again everyone!

-Rob

 

 

Rob

[reivertom]

Those are among the best motors they made. If it has compression, you can figure out the rest!

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Rob

[fleetwin]

Once the roller and sync is set up properly, it will run better.  I know it seems counter intuitive, but the engine will actually run very lean if the throttle opens too soon.

I think you will do better once you can get the engine on a boat in the water and make the carb adjustments then.  Adjust the high speed mixture first, then dial in the low speed needle.

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