possible low compression 2cycle


Old 06-18-01, 07:16 PM
david ahluwalia
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I have a old law boy push mower.1975 or so.I,m having a hard time starting it.floods easy.I,m seeing gas leaking out from under it.I replaced the seal under the blade.(crankshaft seal?) Because of low compression last year and it worked.I however forgot to put the seal retainer back on.I was working so I decided to not tear it back down until it stops working.I have since got it running after drying out the plug.I have a compression of 55 psi ater about 2-3 pulls .Is this to low? Is it time to tear down?
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Old 06-19-01, 07:39 PM
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Hello David

The compression is much too low too.

If you care to attempt to rebuild the engine, consider the fact that there are some special tools needed, you must pay close attention during re assembly also.

Any air leak into the lower end will cause damage to the engine. Air enteing anywhere except through the carb will thin out the fuel mixture and cause the engine to run HOT!

I suggest you visit the local library and local lawn mower shop and buy either a lawn boy repair manual or a generic small engine repair manual that includes a section on two cycle engines prior to starting repairs.

Please read your orginal posting for more information.
If you care to post again on this topic, please use the reply button and not post by clicking the post a question button. Keeping everything on this topic in the same thread helps to follow along. Thanks.

Good Luck,
Accurate Power Equipment Company.
Small Engine Service and Repair Technician.
Personal Quote:
"If it ain't broke, don't fix it until it is broken!"
Bare in mind my company no longer services nor repairs lawn and garden powered equipment. Rest assured and fully confident, the help I offer you is based upon my prior years in this industry, with this type of equipment and is specific and accurate...
Old 06-28-01, 08:20 PM
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david ahluwalia, I can pass on from experience that to tear down a rebuild a Lawn Boy is not cost effective. I say this because you mention going into it I assume to deal with low compression. The parts for Lawn Boy given the age of your mower would best be spent on a new mower. If memory serves me correctly no over size parts are available and to only hone and replace piston and rings is fruitless. If you have never reinstalled the needle bearings on a Lawn Boy crank journal you just don't know what your missing in the way frustration and I have built almost everything that runs from tug boat diesels to Cox 1/2 CI engines....Mike

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