Dual mikuni's 28's running rich

[Dan_]

Bob,
I bet you are going to wind up with something very close to 180s in both carbs and the needles in the middle.   That is after you get the floats set according to the factory dimension, and a 54x20 or finer prop on it.  It sounds like it is bogging from being over propped...

Where is everybody that has ran this setup..?  Chime in...

[Bob Wood]

Dan , Where can I find a factory  spec for float level  for a vm-28 on a 37 hp 1/2 VW? I have not been able to find a thing...

I had always heard 3100 static was the place to be. I suppose cutting down the 54-22 to 54-20 would get my static up around 3400 maybe? 3600 in the air when unloaded.....

[s johnson]

I was running 170's in my Vm28's and clip in the middle slot when I was running dual carbs on my other engine. Also using a Tennessee 54x20 prop. My egts were a little low also and could have went a little leaner but was happy with the climb.  Static was around 3350. The engine just leaked oil like an old Harley. Actually worse.

Scott J.

[Bob Wood]

Hi Scott,

Sounds like where I want to be. I am getting 3100 static now with the 54-22 TN prop.  How did you set up your float levels? did you see less spitting out of the vents when you leaned out the float levels? What EGTs did you see?

Do I sound over proped to you?
Bob

[Bob Wood]

Bob S.

Prop question:  in your previous reply you mentioned a great TN prop you had was a 54-22 cut down to 54-20. did TN Props just shave it down to  re pitch to a 20? Sounds like I may be on that path.....

Bob Wood

[Bob S.]

Yes, Woody... I would go that route if I were you!
It's pretty reasonable, too!

Bob S

[Dan_]

Dan , Where can I find a factory  spec for float level  for a vm-28 on a 37 hp 1/2 VW? I have not been able to find a thing...

Attached...

Make the float arm parallel to the gasket mount surface...  Done.

[Bob Wood]

Dan,
Thanks for this, I did see this and set up accordingly. I thought maybe the L Eagle guys had a different setting....

How did you measure your engine thrust. I  am thinking a  200# deer scale with a hook and rope tied to a trailer hitch or tree??
Thanks,
Bob

[Steve]

How did you measure your engine thrust. I  am thinking a  200# deer scale with a hook and rope tied to a trailer hitch or tree??
Thanks,
Bob

I was on dirt always and had two 4x8 sheets of plywood to put length wise under the mains &  prop to prevent FOD action thru the prop... The plane was leveled up by the top fus longeron... The scale was anchored to a post level with the tailwheel spring  towline connection...

[Bob Wood]

Thanks Steve, will get on that shortly I have a plan.

You mentioned the balancemaster disk a while back, I  looked on their website, very interesting. Saw a couple planes in our group with them.

I have the Mosler counter balance weight on my motor, since the balance master device disk is cup shaped my counter weight would have to clear the outer edge. The plane I saw it on had no aluminum prop ring over the balance disk. If I did it that way my counter balance would not clear the balance device. I assume this thing will not take the place of the counter balance. Have you seen these mounted with the 1/4" prop ring over the device? If I did that I think it would fit fine.

Thanks for input, I am going to give them a call tomorrow,
Bob

[Steve]

Thanks Steve, will get on that shortly I have a plan.

You mentioned the balancemaster disk a while back, I  looked on their website, very interesting. Saw a couple planes in our group with them.

I have the Mosler counter balance weight on my motor, since the balance master device disk is cup shaped my counter weight would have to clear the outer edge. The plane I saw it on had no aluminum prop ring over the balance disk. If I did it that way my counter balance would not clear the balance device. I assume this thing will not take the place of the counter balance. Have you seen these mounted with the 1/4" prop ring over the device? If I did that I think it would fit fine.

Thanks for input, I am going to give them a call tomorrow,
Bob

Mine runs under the prop crush plate on the front side of the prop - think Scott Johnson has his mounted that way too... BTW: I have a Prince UL prop 54x20 with a 4" bolt pattern - I'm going to the shop tomorrow - is that something that would work for you?... The prop has never been taken out of the box - I think it's in there... Long story on that...

[Bob Wood]

great I am  going to do the balance master.
I have to check now but Scott Casler called my mosler the large hub..My prop has the 2" counter bore pilot hole.
I have to check to see if the spacing was 3 1/8 or 4"
Yes I may be interested in that prop if it fits.

Bob

[Sam Buchanan]

great I am  going to do the balance master.
I have to check now but Scott Casler called my mosler the large hub..My prop has the 2" counter bore pilot hole.
I have to check to see if the spacing was 3 1/8 or 4"
Yes I may be interested in that prop if it fits.

Bob

One of the cardinal rules of engine troubleshooting is to only change one variable at a time.

Wouldn't it be best to get the carbs straightened out before considering other stuff like balancers? Uneven carburetion can play havoc on engine smoothness.

[Bob Wood]

Well said Sam, I am going to finish the carbs before I put on the balancer and try a  different prop. I reset the float levels and ran up earlier in the week and I saw my temps pop up faster on the LED gauges, i had my 120 and 115 jets in and when I hit 3/4 throttle it was cutting out.  That never happened before unless I had the 105 jet in one side..... I had 1 float low and the other higher than the book....So  I am going back to the larger jets and looking at temps again. Seems like I am almost there...I would assume now I am on the lean side of peak on that bell curve....When I get my temps up around 1200-1300 I will do the thrust test. Waiting for the rain to quit and the temps to get over 50!!

Want to get this bird in the air before the snow flies, which may be soon in Wisconsin!!

Thanks again for the pointers!!,
Bob

[Bob Wood]

Steve K,

My Mosler hub is a 6 bolt 3 1/4" hub with the 2" counter bore.  Thanks anyway if I get to that down the road maybe somebody in our group may have one.  I am finishing the carbs before I do anything else. I think I am close...

Thanks,
Bob