Engine issues (video included) (2024)

I'm guessing that I have issues with crank seals, but can anyone watch this video and listen to engine to give a heads up on what could be going on? Engine misses, adjusting carb doesn't seem to help much. One straight it may be fine, the next it's falling on its face. Mikuni on alky.... .100 timing. Rotax DSC rotary. EGT stayed between 600-700 all day.

I appreciate the help if any can be given. You may reply here or on the video comments.

giwprez said:

I'm guessing that I have issues with crank seals, but can anyone watch this video and listen to engine to give a heads up on what could be going on? Engine misses, adjusting carb doesn't seem to help much. One straight it may be fine, the next it's falling on its face. Mikuni on alky.... .100 timing. Rotax DSC rotary. EGT stayed between 600-700 all day.

I appreciate the help if any can be given. You may reply here or on the video comments.

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No help on the engine hear, but this looks awesome! Would love to race in this.

Bradley71 said:

It just sounds really fat on top.wheres ur needles set.

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I had inital setup on 1 1/2 L and 1 1/2 H. Ended up around 1 1/2 L and 1 1/4 high. It just never really cleaned out. I agree, I believe it's a carb issue without question.

Bigeasyebo said:

No help on the engine hear, but this looks awesome! Would love to race in this.

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That looks like cridersville speedway in Ohio.

IDK. EGT seems really cold. Maybe try another carb????

I would think if you were having issues with the seals, it would be running lean.

Brian #89

Strikes me as an ignition problem. Sure, it’s fat on the high jet but it’s also not really getting a chance to fully clear itself out.

Do you have an RPM readout? Might be worth checking if there’s a loss in ignition signal. If you have a means to hand choke that can help isolate leaks and fuel delivery issues on track.

RadialFin said:

Strikes me as an ignition problem. Sure, it’s fat on the high jet but it’s also not really getting a chance to fully clear itself out.

Do you have an RPM readout? Might be worth checking if there’s a loss in ignition signal. If you have a means to hand choke that can help isolate leaks and fuel delivery issues on track.

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I haven't downloaded the mychron data yet .. so hopefully that can lead me towards what's happening as well. I need to have a closer look at the egt to see if it's detonating.... I do know that the gear ratio I'm running, this thing should be screaming... But it maxed out at 13k. I can try another carb and a different coil... Unfortunately, I don't have another option for the stator.

phantomkartracer said:

Did you happen to try a new spark plug?

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I did switch plugs. 2413 autolite

giwprez said:

detonating.... I do know that the gear ratio I'm running, this thing should be screaming... But it maxed out at 13k.

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Yeah they will spin as high as 19k if you let them. For an oval of course, no point in going that high. Detonation should be easy to tell from the piston crown, maybe you’re not able to get at the kart right now? Pull head or header off and have a peek.

What ignition is on it? PVL or Motoplat?

Fresh fuel?

Yikes. RIP piston. I'm impressed it didn't lock up. Time to do a pressure test on the engine and carb. Make sure you're not leaking at the rotary valve cover gasket too.

Yeah those motoplats are hard to find and not cheap when you do find one.

RadialFin said:

Yikes. RIP piston. I'm impressed it didn't lock up. Time to do a pressure test on the engine and carb. Make sure you're not leaking at the rotary valve cover gasket too.

Yeah those motoplats are hard to find and not cheap when you do find one.

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Any certain standard pressure an engine should maintain?