Ok all of you engine experts. Need some help. I am getting frustrated with my 91. Seems like we have set the needle valves all over the place. Replaced the glow plug and fuel lines. My engine keeps surging during flight. Also if I cut back the engine too soon on landing it will dead stick. Any suggestions? I never have adjusted the valves, however one of my friends said that would not help my problem. The engine is probably 2 years old now. Help !!!

My 91 Surpass possed a similar problem. I found that the needle valve was moving during flight. I slipped a piece of fuel line over the needle and spring, solving the problem.

You might try just giving the carburetor a good cleaning by disassembling and washing all of the parts, etc.

Both good ideas to try... any others??

All the usual suggestions for problem engines....

check for air leaks, tighten up all nuts and bolts, new fuel, clean out carb, set HSN LSN to instruction sheet innitial settings, hotter plug, colder plug, different brand plug etc etc

I'm not sure that checking the valve settings wouldn't atleast allow you to rule them out ?

Be methodical and try one thing at a time....

[edit] sorry - take her out and do all this on a test bench to remove a few variables from the equation....

good luck!