Author Topic: Poor performance (Read 211 times)

Gary Buscombe · « **on:** November 01, 2026, 09:37:56 AM »

My pilot friend & mechanic test flew LEXL with 45hp Casler engine; said it wouldn’t climb more than 50-100 ft per minute.
Shouldn’t it climb 500-600 rpm at 700’ elevation in Oklahoma?

Chuck in Indiana · « **Reply #1 on:** November 02, 2026, 05:04:45 AM »

Yep. Could be many things including prop.

Gary Buscombe · « **Reply #2 on:** November 02, 2026, 05:43:06 AM »

He is checking this week the twin Mikuni carbs; the valve lash was fixed. The plugs were sooty.

Chuck in Indiana · « **Reply #3 on:** November 02, 2026, 01:34:51 PM »

I run VWs at ,005 intake and .07 ex.
About all sooty plugs tell you is idle mixture. To find out what it's doing at cruise, you need to cut the plug away and look at the insulator. It should have a brown ring where the insulator flares out into the shell about 1/8" wide.

Brock · « **Reply #4 on:** November 03, 2026, 09:02:08 AM »

Quote from: Chuck in Indiana on November 02, 2026, 01:34:51 PM

I run VWs at ,005 intake and .07 ex.
About all sooty plugs tell you is idle mixture. To find out what it's doing at cruise, you need to cut the plug away and look at the insulator. It should have a brown ring where the insulator flares out into the shell about 1/8" wide.

Chuck, how do you cut the plug? Have any pictures?

Kamcoman77 · « **Reply #5 on:** November 03, 2026, 09:03:51 PM »

Carbide wheel to cut plug metal off insulator. Here are photos of plugs in various mixture conditions. These should be from full throttle runs with clean cutoff of ignition. Once you get main jet correct for full throttle, you adjust mid-range with tapered needle position.