Any Lawn mower techs?

[BuzzStPoint]

Re: Any Lawn mower techs?

Here's what I have so far.

Pulling slowly on the cord doesn't sound like air leaking out.
Putting a compression tester on it will result 59-60psi in 2 pulls.
Applying air to the cylinder, has different sounds..
I'm not too smart on small engines so there may be a difference to auto engines.

When I apply air and rotate the engine. air will come out the carb. (intake valve open) rotate further air stops from carb and sound to go tot he muffler ( exhaust) keep rotating sound changes significantly to exhaust.
So question is, should there be a "sealed" period like in automotive engines?
If so, then there is an issue with the exhaust valves.

 

[halfmoa]

Re: Any Lawn mower techs?

Here's what I have so far.

Pulling slowly on the cord doesn't sound like air leaking out.
Putting a compression tester on it will result 59-60psi in 2 pulls.
Applying air to the cylinder, has different sounds..
I'm not too smart on small engines so there may be a difference to auto engines.

When I apply air and rotate the engine. air will come out the carb. (intake valve open) rotate further air stops from carb and sound to go tot he muffler ( exhaust) keep rotating sound changes significantly to exhaust.
So question is, should there be a "sealed" period like in automotive engines?
If so, then there is an issue with the exhaust valves.

There has to be a "sealed" period to generate compression. Pull the head.

 

[Jlawsen]

Re: Any Lawn mower techs?

I had a Honda that gave me a similar problem. Mine was oil in the air cleaner from when I turned it on its side and powerwashed it. Changed the air cleaner and was back to 1 pull starts immediately.

 

[BuzzStPoint]

Re: Any Lawn mower techs?

Here's what I found.
The exhaust valve doesn't seem tight. Meaning at closed position, the valve seems loose, you can move it around and spin it.
Tried taking a video but didnt' turn out.
When I removed the valve spring, there's a lot of side to side play in the valve. No obvious wear on the valve itself.

Now to the parts catalog, can I buy the valve journal or are those molded in?

Edit......

Looks like there is no valve journal.. Only valve.
Could be the valve is worn, (don't have a micrometer to check). Replacement engines are just as much as the mower is.

 

[markheck1]

Re: Any Lawn mower techs?

The valve might make it stop, but i still lean towards something in the carb.....

Unfortunately those cheaper mowers are getting to be throwaways when they start having problems....

 

[halfmoa]

Re: Any Lawn mower techs?

Unfortunately those cheaper mowers are getting to be throwaways when they start having problems....

IDK if Tecumseh has went this far, but some of the cheaper Briggs engines are made with plastic (IDK what material but it's sure as heck not steel) camshafts with steel lobes....shameful.

 

[BuzzStPoint]

Re: Any Lawn mower techs?

So here's what it is..

Wobble in the Exhaust valve.
The Ext valve seat has a ridge on it.

So my last ditch effort for this sucker is this. Buy a new valve, hand remove the burr off the edge of the seat, and replace the head gasket. Perhaps that will get me through the summer with this thing.

 

[halfmoa]

Re: Any Lawn mower techs?

Any indication what caused the burr in the seat? That's not good! If you polish the burr out will the valve seat properly?

 

[dolluper]

Re: Any Lawn mower techs?

Putting a compression tester on it will result 59-60psi in 2 pulls. your quote......what was it on one pull 30....my guess .....you need three or more pulls on these engines with no oil injected.......if you didn't damage the head gasket reuse it ......get some valve grinding compound and a suction cup stick and clean up valve+seat......you twist the stick like trying to start a fire between your hands......throw her back together after cleaning off compound .......adjust the governor and go from there......these motors will run with tons of slooop...hard to kill them
watch this video
http://www.youtube.com/watch?v=6BX5ab12-Wk

 

[WIMUSKY]

Re: Any Lawn mower techs?

Unfortunately those cheaper mowers are getting to be throwaways when they start having problems....

There's the issue. The cheaper mowers are meant to be thrown away rather than be fixed. Along with many other products. Sadly, we've been living in a throwaway society for quite some time.

I believe it was said it's a $125 mower. I wouldn't waste too much time or money on it..... JMO

 

[Tim Frank]

Re: Any Lawn mower techs?

So here's what it is..

Wobble in the Exhaust valve.
The Ext valve seat has a ridge on it.

So my last ditch effort for this sucker is this. Buy a new valve, hand remove the burr off the edge of the seat, and replace the head gasket. Perhaps that will get me through the summer with this thing.

Per Dolluper's post, that may get you off and running.....but I'd still bet on the carb.
This is a deja vu of my mower last spring, and after doing the exhaust valve (it was just a carbon ridge but I don't think it really interfered all that much with the valve sealing) I had to go back and redo the carb....then it was clear sailing.
In fairness, there was probably some improvement in performance from lapping in that valve and I probably should have done the intake valve too, but I cut that corner because itr was still better than the exhaust valve.

Good luck.
If you need any specs for that motor, PM me, I have the Tecumseh OEM manual for anything under 10 HP.

 

[BuzzStPoint]

Re: Any Lawn mower techs?

Dolluper, Didn't check compression on 1st pull just till the needle stopped moving.
You could pull it twice till it got up approx 59-60 psi and no more.. If you really gave it a good pull it would go 61 but no more. More pulls doesn't raise the PSI

As for the head gasket, I can see material pulled off of it.
What caused this ridge? since is looks to be on the block and not the seat my guess it was the sloppyness of the valve banging around the edge. .

I've already bought a 12 dollar carb kit, 7 dollar primer bulb. So another 20 bucks for the valve and gasket will be all she wrote.. I got a guy near me that will by it for 10 bucks.

As far as a throwaway, I hate that... I'm old school, like to tinker with things.
My neighbor gave me a gas powered leaf blower/mulcher. Could only get it running for a few seconds. he just went out and bought a new one.
4 dollars in parts (piston ring, head gasket) it's running great.