Engine dies on acceleration

richyrich7 · « **on:** August 29, 2008, 20:11 »

I've got a second 2 stroke mantis that I'm trying to get up and running, I keep going back to it on idle days.

Anyway that's the problem I've got I think the chap who had it before me tried to adjust the high and low idle screws. I've took them back to locked and re set them, the engine will idle no problem but dies on acceleration.

Any ideas would be most welcome.

Gwiz · « **Reply #1 on:** August 30, 2008, 05:26 »

sounds like the high speed screw needs to be turned out a bit more. OR it could be that the exhaust port/exhaust is blocked with carbon.
metering diagphram sometimes gives the same problem, or partialy blocked fuel filter.
my moneys on the first two though....

richyrich7 · « **Reply #2 on:** August 30, 2008, 09:35 »

Cheers Graham I'll give it a go later today.

Bigbadfrankie · « **Reply #3 on:** August 31, 2008, 20:12 »

I go with gwiz . not because i know anything but he does. Have you read the thread from Shaun on stroker tuning.

richyrich7 · « **Reply #4 on:** August 31, 2008, 20:18 »

Yes thanks frankie I've read shauns post, thats what got it going again following them instructions that and Grahams advice on carb cleaning. The chap I got it off openly admitted that he knows diddly about engines and thought it a good idea to twiddle the screws :roll:
I've not managed to have another go with it yet and was unsure how far out you can turn the high idle screw.

Bigbadfrankie · « **Reply #5 on:** August 31, 2008, 20:39 »

you have check compression :shock:

richyrich7 · « **Reply #6 on:** August 31, 2008, 20:46 »

Quote from: "Bigbadfrankie"

you have check compression :shock:

Apart from putting my thumb over the spark plug hole nope. I can get it running no probs, can lack of compression cause it to die then ?

Gwiz · « **Reply #7 on:** September 01, 2008, 05:32 »

on a two stroke, a lack of compression would make it hard/impossable to start. It mighjt be worth shining a torch through the exhaust and the intake ports. scoring on the side of the piston would show up easy. If it is scored then it's been seized in the past, you might want to then look at it as parts for the other one, rather than throwing money at it. :roll:
sometimes a two stroke will run well for about ten mins, then fade and die. If that happens, look at the piston, before opening the wallet........

Thank you, Frankie, for the kind words

shaun · « **Reply #8 on:** September 07, 2008, 11:15 »

hi chaps,very fine adjustment on the screws,very very fine adjustment

richyrich7 · « **Reply #9 on:** September 07, 2008, 12:07 »

Hey up Shaun nice to see ya back matey

shaun · « **Reply #10 on:** September 07, 2008, 12:12 »

no probs pal

yodapete · « **Reply #11 on:** September 10, 2008, 17:50 »

Hi Richie, you've probably got the Mantis sorted by now but if not, have you tried putting fresh fuel in. I bought a 2 year old Mantis that did exactly the same as yours. It would start and tick over but when I tried to rev it, it died as though starved of fuel or choked. I tried everything, completely stripped carb looking for blockages, checked exhaust-everything OK. Finally got it running OK only to do exactly the same a few months later. I found out that it's VERY fussy about old fuel. There were a few pages on the Mantis web site that stated never to use 2 stroke mix more than 14 days old. Old fuel should be emptied out, pumped through the carb using the primer bulb and new fuel put in. Prime again with the primer button, leave for 1 hour to soften any gunge in the carb then start as normal. I only mix 1/2 litre of fresh fuel now and ditch what's left when I've finished and I get no problems at all. The chap on the next plot has an old Mantis, leaves fuel in over Winter and it starts fine. Guess mine's just a bit fussy. Hope this helps.
Regards

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Engine dies on acceleration

Gwiz

Gwiz