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Engine basics => Engine set up tips => Topic started by: Dennis Toth on April 23, 2019, 11:17:03 AM

Title: Rough running engine at start?
Post by: Dennis Toth on April 23, 2019, 11:17:03 AM

Guys,
Had an unusual experience this morning at the field with my normally reliable OS Max25. Seems my glow driver was a bit weak and the normal starting procedure didn't get it. I pulled in a few more cough primes and started flipping, nothing. I checked the glow driver and it seemed it was done. I clean the center contact and got a glow. Connected up and in a few flips the Max came to life but started vibrating very rough. Then it cleared but did one more rough spurt then cleared and ran fine. Just wondering it others have had this happen and what you think caused it? I think it might have just been a little flooded and had to blow the excess out. What do you think?

Best,   DennisT 

Title: Re: Rough running engine at start?
Post by: FLOYD CARTER on April 23, 2019, 05:15:24 PM

Strange.  Usually, a flooded engine will do nothing.  If you dry out the top end, it might burp and stutter for a second while the crankcase charge gets used up.  After that, should run normally.

Title: Re: Rough running engine at start?
Post by: GERALD WIMMER on April 24, 2019, 06:08:12 AM

Hello
Sometimes a plug that is on its way out behaves like a plug that is too cold. I would try a new plug or hotter plug if it does it again but again it may have just been loaded with raw fuel and oil that needed to clear as stated.

Regards Gerald

Title: Re: Rough running engine at start?
Post by: Steve Helmick on April 27, 2019, 06:47:52 PM

Carboned or oiled up glowplug would be my guess, too. Or, the glowplug is not the correct choice? y1 Steve

Title: Re: Rough running engine at start?
Post by: RknRusty on April 27, 2019, 10:31:59 PM

Any of the above, and maybe too much after-run oil in the crankcase and combustion chamber.
Just guessing though.  LA or FP .25, probably nothing serious.
Rusty