OT: any small engine mechanics here?

Last I checked mine it was about 85psi but it isn't a Sears. When mine stopped running so also checked compression. I found the exhaust all caked up with carbon buildup. Mine had a screen in it that was clogged - Cleaned it and it started right up.

A friend of mine told me a bit once that the weateater motor is sometimes used for RC airplanes because the compression is lower than most -- makes it easier to start, I guess. It could be that your 32psi is normal but maybe someone could check that for you.

thanks for the reply Remco....yeah i believe the compression to be too low...the exhaust is clear as is the "intake" tract....this weed eater had been a victim of a "flood" in my basement, and i believe it may have gotten some muck in it that possibly scored the cylinder/piston/rings...haven't taken it that far apart, because its just not worth it(the "flood" happened a couple years ago, and the engine still ran but i believe it has progressively gotten weaker..)...LOL....i had thought that it "should" be enough compression to start it however considering the path the fuel has to take i believe the low compression will keep the fuel from becoming "airborne"(atomized)... it must travel from the carb to the "crankcase" then through the port to the cylinder...i feel the compression being low does not allow enough "suction" to complete this process...anyone else agree? Speedy you there?

yes some larger scale airplane modelers conver the weedeater engines for their planes....my planes are much smaller than that...

Maybe I am stating the obvious, but you could squirt a little oil in the head to see if the compression increases. Once the rings, etc, are shot those little engines tend to be toast, though.. (but again: probably stating something you already know)

i had considered doing a "wet" compression test, but as i said its not worth it...got too much time in this junker already...if the compression is low, as i believe it is, it is much cheaper to replace than to repair....but thanks for the suggestion.....

I'm not familiar with the particular engine, but if the intake tract is into the crankcase most twostrokes will have either a reedvalve or rotary valve. Too cheap for a rotary valve, but there may be a reedvalve and they sometimes don't seal well. The most likely culprit is not the low compression per se but the pumper carb needs vacuum pulses to operate the diaphragm. Try a shot of 30 weight or so into the cylinder, spin it over, squirt a shot of ether in there, screw the plug in a few turns by hand and give it a try. I suspect after you get it to fire a few times like this it will likely keep running and probably make it through another season.... UNLESS you left gas in the carb last time you ran it, in which case my advice is to throw it away! Always shut the fuel off on small engines and run them til they die. There are some excellent fuel stabilizor / oils available that help considerably, but our gasoline these days destroys carbs. My opinion... -BaH

thanks Busman...i will give it a shot...no gas was left in it, i "winterize" all my small engine equiped tools.... it has lived for 9 years now, so i'm thinking it is tired...will know tomorrow...i did make it a *strong* promise that i would find a new home for it if it did not start...the new home will be the county landfill...

................There's an old trick to un-stick that reed valve that worked for me once on my 6 hp Mercury outboard motor. Blast compressed air into the spark plug hole while you're turning it over to pop it open. I asked an oldtimer what he was doing when I saw him doing this way back when I was about 13.

...............Let me try to re-explain myself. The compressed air is supposed to make the reed valve seat itself when stuck open.......I think. The long term problem with them is that they lose their tension from heat and metal fatigue which makes them prone to not seating properly.

..... Thanks for the tip Tim...will try it...this trimmer has been great...would hate to see the cheap son of a gun go....LOL...i did however replace it last year....with what i thought was a *good* troybilt 4cycle trimmer.... it was good...the three times i got to use it before it partially self-destructed..

What did you do? Put 2-cycle engine oil in the engine? *snort* Oh... wait... That was me who skillfully instructed my wife on the importance of putting 2-cycle oil in our lawnmower's 4-cycle engine. With God as my witness, I thought turkeys could fly. Uh, I mean that it had a 2-cycle engine. It never stood a chance, but it bravely powered that mower long enough (for my wife) to cut about half of the lawn before "sumthin' shook itself a-loose." It never ran again.

"Stupid people are funny." - me

(with oil injection so you don't have to pre-mix, that is.)

"Stupid people are funny." - me

not sure that was you problem shag...mixing the gas in a 4stroke with 2cycle oil can cause plug fouling and buildup in the cylinder, but usually doesn't lead to catastrophic failures....Me thinks Kim killed it so she wouldn't have to mow anymore...LOL

aha....disreguard the last post...you really are stooopid.....J/K....LOL....

.............It amazes me that there are any American women left who still mow the grass or shovel snow. None of the ones that I know at home and at work have any inclination to step up and keep us middle-aged males from collapsing in a snowbank while clutching our chest with one hand and a shovel with the other. Women outlive men because the men are doing most of the heavy lifting.

I mow, I weed eat, I dig trenches, I put together irrigation systems, I relocate 300 lb trees with nothing but a wheelbarrow and a useless MAN standing there scratching his head because he's too stupid to figure out the lever system, I edge, I use the leaf blower, I plant, I remove sod, I take loads of sod and debris to the dump where I shovel it off because our company cant yet afford a dump trailer, I trim hedges, prune trees, and once upon a time I carted the engine out of my bug and hauled it across the lawn on a piece of plywood, with the help of *gasp* another female who does the same things herself. I guess Florida girls must be bred better than the New Yorkers you're used to.

K.

Good to hear about a woman doing as she's told! :-D

"Stupid people are funny." - me

Now, I could make a comment about florida girls being bred better, but I will refrain. Really.

My wife usually does all the mowing, etc also. I do the snow as shes just a tad bit to short to work the snowblade on the tractor but if it requires shoveling, she's out there. She's not afraid of doing any kind of work thats need to be down around here.

Randy

I read the other day about a Florida Chick who wore her mini-skirt to the grocery store. Bent ove to get milk, and got bred instead.

( is that the same thing????)

LOL

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MUADIB®

Mary Jane's mother gave her $10 to go into town to get some felt. Mary Jane laughed and laughed because she knew she could get felt for free.

"Stupid people are funny." - me