Mklll Anti Backfire Device Adjustment

chasesa · Dec 10, 2014

Looking for comments on adjusting the AB device.

I know it requires 50 ft-lbs torque setting. I made the special tool with socket and thrust washer, per Old Britts.

Questions:
Does the AB device turn clockwise when testing slip?

If slip is less than 50 lbs torque, is AB device slip "tightened" with the large nut on the disk spring side?

How do you keep that nut from loosening?

What is the consequence of slip at less than 50 ft-lbs torque?

dennisgb · Dec 10, 2014

chasesa said:
Looking for comments on adjusting the AB device.

I know it requires 50 ft-lbs torque setting. I made the special tool with socket and thrust washer, per Old Britts.

Questions:
Does the AB device turn clockwise when testing slip?

If slip is less than 50 lbs torque, is AB device slip "tightened" with the large nut on the disk spring side?

How do you keep that nut from loosening?

What is the consequence of slip at less than 50 ft-lbs torque?

I haven't had mine apart yet, but you want the slip in the direction of starting rotation according to the Old Brits article (I think that is clockwise). Slip is set to 50 lbs. Once you get it set you lock the nut with the tang and Loctite so it doesn't loosen. If the slip is less than 50 lbs it might not turn the engine over...it will just slip.

L.A.B. · Dec 10, 2014

chasesa said:
Does the AB device turn clockwise when testing slip?

It doesn't matter. It slips in either direction.

chasesa said:
If slip is less than 50 lbs torque, is AB device slip "tightened" with the large nut on the disk spring side?

Yes.

chasesa said:
How do you keep that nut from loosening?

Once set, the nut flange is peened into the groove. This is mentioned the Old Britts article which also recommends using green Loctite.

https://www.oldbritts.com/e_start_backfire.html

chasesa said:
What is the consequence of slip at less than 50 ft-lbs torque?

The AB device will tend to slip more readily instead of the crankshaft turning.

chasesa · Dec 14, 2014

Why worry?? Sent the AB unit to Fred Eaton to adjust.
$65 plus shipping each way. I'll install and be done.
SC

jaydee75 · Dec 14, 2014

I set mine to 46 ft-lbs, trying to be safe. It works fine, but only occasionally slips just like sometimes it's harder to kick than others. No harm done. It's really a very simple mechanism. I think the torque wrench may have +- that much variation.
Jaydee

chasesa · Dec 14, 2014

Prior to sending to Fred I made-up the adjustment tool. On checking and re-checking the torque was 45 ft-lbs.

The target setting is 50 ft-lbs. I could not attain that number, peen the nut, etc.

Now, I can do a lot of "stuff", but on this item It was a lot easier to send it to Fred. Happy trails!
Stephen

Mklll Anti Backfire Device Adjustment

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