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 Has anyone removed compression release on their lawnmower engines?

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motorhead45102
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PostSubject: Has anyone removed compression release on their lawnmower engines?   Has anyone removed compression release on their lawnmower engines? Icon_minitimeApril 27th 2010, 9:32 pm

I have a question has anyone removed compression release on their lawnmower engines, ive done it to my 3.5hp briggs, and my freinds 12 hp I/c engine, and before i worked on his engine it would hardly run at all, but i worked on it and i noticed it had compression release, which it was compression releasing the whole time the thing would run, so i ground the valve stem down, just a hair and the valve(intake) closes when the piston goes from BDC to TDC, so it has a whole lot more compression and it actually runs way better, and it seems more powerfull too, maybe cause it has high compression now. idk, but it works and not really any noise either from alittle gap on the valve stem, about a feeler gauge kind of a gap. but i feel sorry for his engine, cause we got these header pipes off of a vtwin engine and he just wants to run straight header, which the pipe isn't all the way near 12 in. and flames shoot out about almost a foot from the pipe, so i think he is going to burn up his engine, but me on the other hand, im using the other header pipe, and im going to put a quad muffler on the pipe so it would get a good sound with having backpressure.
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Chunk
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PostSubject: Re: Has anyone removed compression release on their lawnmower engines?   Has anyone removed compression release on their lawnmower engines? Icon_minitimeApril 28th 2010, 2:47 am

Thats something I want to try on an engine too. And skimming the cylinder head.
Shame he's gonna ruin the thing!
I like your style man, I dont think straight pipes are always the answer. You normally get a much nicer sound with some kind of muffler, plus your motor wont burn up a valve!
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motorhead45102
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PostSubject: Re: Has anyone removed compression release on their lawnmower engines?   Has anyone removed compression release on their lawnmower engines? Icon_minitimeApril 28th 2010, 6:40 am

yup, thats what im after, a good sounding engine without burning it up.
also i started my engine up and forgot i have no oil in it, do you think its fine, i only ran it for maybe 30 secs? idk how long i ran it but it wasn't long i was just seeing how the muffler would sound. well ill say that i didn't run long enough to even remotely warm up, god why did that happen, but i checked her out she seemed ok for that little bit.
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dangeroustoys56
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PostSubject: Re: Has anyone removed compression release on their lawnmower engines?   Has anyone removed compression release on their lawnmower engines? Icon_minitimeApril 28th 2010, 7:00 am

Well, you can run straight pipes- but they haveta be long enough and a couple bends for some back pressure .

The compression release is there to be able to start a high compression motor - i would think itd be harder to start w/o it.

Oddly my lil 5HP briggs toro has a muffler and still shoots a lil bit of flames out ( and muffler glows bright red) and thats all stock- i might do some changing of that setup- sometimes my foot slips and i burn my sneeker....
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motorhead45102
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PostSubject: Re: Has anyone removed compression release on their lawnmower engines?   Has anyone removed compression release on their lawnmower engines? Icon_minitimeApril 28th 2010, 10:35 am

well the engine has mechanical compression release meaning even if the engine was revving 4,000 its still releasing compression, so without the mechanical release it is harder to start, but once started it has more compression, i may just leave my valve train stock cause, it requires alot of battery power to turn the motor over, mean we hooked up my freinds mower on to his car and it was still lacking some juice to crank it over as if it still had compression release, i would like to get a cam with automatic compression release so i can have ease of starting but lots of power once started. anyone know where i could get a cam? also were would i take my head to have it milled. that would give me more compression wouldn't it?
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Chunk
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PostSubject: Re: Has anyone removed compression release on their lawnmower engines?   Has anyone removed compression release on their lawnmower engines? Icon_minitimeApril 28th 2010, 11:25 am

Yup, having the head skimmed = more compression.

Running it with no oil will do it no harm unless it really warms up. I ran mine for about 5 mins with no oil once (forgot there wasnt any) and it was totally fine, still not warm. PLus there's always gonna be a bit of oil left in the cylinder.
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PostSubject: Re: Has anyone removed compression release on their lawnmower engines?   Has anyone removed compression release on their lawnmower engines? Icon_minitime

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