9 replies to this topic

[Phluphy]

Loping engine:

First, I only use non-ethanol gas, the loping eased considerably,would someone have made carb adjustments to compensate for something I haven't found yet?

Sprayed carb inside and out loping eased even more.

Checked, cleaned plugs, loping eased more and now the idle is too high i.e. as if it were on 1/4 throttle.

Checked compression...good @ 120-125, doesn't hold it long, few seconds

Tinkering with idle adjustment today.

Any recommendations?

BTW, this is a B&S model 422437 type 1209

 

Loping cured...someone had the idle mixture fiddled with, I suppose, in their opinion, to cure another problem.

Now it purrs, eh, such as a B&S does, definitely not a Onan.

Edited by Phluphy, July 08, 2015 - 03:47 PM.

[jimbobbillyray]

well, I know that on older Kohler engines with a walbro carb, the throttle shaft can cause some wear on the hole where the throttle shaft passes thru the carb.  they make a kit to replace the bushing where the throttle shaft goes thru there, and doing this repair will cut down on the air intake to the carb and stop the loping.  I did the bushing replacement on a carb for a k341 kohler on a john deere 316. once.  ran great, idled perfect after the repair.

[glgrumpy]

This was that single vertical engine?  Does it have both idle mix and main jets to adjust?  Some may have just the main jet. Have you tried adjusting either one? Main is when wide open, the idle mix, not just the speed, the mix screw when idling. Best done when is warmed up. Governor's can be problem too, is it moving free and have good spring from it to the carb and not all stretched out? Water in gas tank and getting into carb? May need to pump or dump out the older gas, let it dry in the tank and start with good 91 octane fuel.

[Phluphy]

No glgrumpy, it's a B&S horizontal 18 hp twin.

[larrybl]

Check the carb shaft, any play will cause lopeing. I have some lopeing with RED 18 opposed briggs while not under load, a little choke settles him down. Once I turn the deck on, I push the choke in and go WOT with no issues. 

[larrybl]

Could you have adjusted the idle screw instead of the metering jet?  "loping eased more and now the idle is too high i.e. as if it were on 1/4 throttle."

 

http://www.mytractor...ing-solved.html

[Phluphy]

Could you have adjusted the idle screw instead of the metering jet?  "loping eased more and now the idle is too high i.e. as if it were on 1/4 throttle."

 

http://www.mytractor...ing-solved.html

That image is exactly what I have, and yes, it was the idle mixture screw I adjusted today.  Not even sure where the metering jet is.

[larrybl]

That image is exactly what I have, and yes, it was the idle mixture screw I adjusted today.  Not even sure where the metering jet is.

I think the metering jet is fixed on the inside. I can check on one of mine when I get home.

[larrybl]

OK, there are two types of these carbs. The old style has a metering adjustment screw, the new style has a fixed internal metering insert. Best you can do on the internal is to clean / replace it.

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[Phluphy]

I think the metering jet is fixed on the inside. I can check on one of mine when I get home.

Yes it is a fixed jet.  After removing the plug I gave it a good dose of carb cleaner.  I wasn't aware of the name of that particular part until after you mentioned it.

Edited by Phluphy, July 09, 2015 - 11:17 AM.