gcv160 not starting... scratching my head

[lawnboater]

greetings I have GCV 160 Mower. My model is GJAE-4310443 S3a

This will not start:

Spark- yes with tester and just plug against ground
Compression- 65-70
New Carb (that was fun)
Brake on
Valves adjusted 6 intake 8 exhaust (think i got it right Set them when both were jigggling and when kind of a lobe on the black gear is at the top)
Spraying starting fluid into intake and spinning with drill I will get a pop after 10-20 seconds spinning
Same if putting some fuel in plug hole.

The symptoms are the same prior to valve adjustment. I do notice that the part hitting the rocker does not seem to be centered. Thinking maybe bent push rod?
Also I put inspection cam down plug hole. Piston is really covered in carbon. Hard to see walls but do have compression.

Just wondering what you guys think before I decide to tear down some more.


Thanks
Ralph

 

[Scrubcadet10]

a few questions
Has it been sitting all winter and you're wanting to get it started?
Or has it been Running fine and just quit running
Or, did you hit something with the blade and it quit?

 

[slomo]

Piston is really covered in carbon. Hard to see walls but do have compression.

Check your engine manual for the decarbonizing procedure and when it should be done.

If you wait too long and small chunks of rock hard carbon get into the cylinder, it will score the bore killing the engine. It will start burning oil......

Below are critical items that almost never get looked at. These are for all mower engines. Even 2 strokes need carbon cleaned out.

1.Decarbon cylinder and valves
2.Clean block and cylinder cooling fins.
3.Valve adjustments.

 

[sgkent]

as someone else suggested, when is the last time it ran right, and why did you replace the carb?

 

[bertsmobile1]

And as much as I never trust the numbers people quote for compression, 60-75 is a big variation and right on the border line of too low to fire .
If those numbers come from a screw in compression tester then either you have a bad technique or a big compression leak.
So we are talking glazed bore & worn rings , malfunctioning decompressor , worn vale , bent valve , loose valve guide.
A leak down test is ddefinatly required

 

[lawnboater]

thanks guys. I found this mower and tried the new carb for the heck of it. When I get some time I will pull off the head and dig in further. Pretty sure this has decompression feature that bumps one of the valves.

 

[sgkent]

you have to determine what is missing. spark, fuel to air, or compression. get yourself a borescope on Amazon for $17 and watch the valves open and close. If both do that and you have compression then you can rule that out. https://www.amazon.com/gp/product/B07PBF6DX5/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[WallaceRoger]

I'm having a similar issue, I picked a mower from the trash on our annual spring cleaning day. Mower had old nasty gas in it, a bad safety control cable and the air cleaner had pretty clearly never been changed. Took the carb all apart and sprayed it out with cleaner, got a gasket kit for it and put it back together. I got it started with some ether, but the governor was surging and it would only run on full choke. So I pulled it all back apart and ran it though the ultrasonic cleaner three times, then blew it all out with carb cleaner again. Reassembled, this time used some permatex on the gaskets. The surging is gone and it runs ok, but the mower still will not start without hitting it with ether. Spark is fine, plug was not too bad when I checked it and the gap was correct. The only thing I haven't done is check the valves, but it seems like ether wouldn't help if that were the issue.

Can't figure it out.

 

[sgkent]

I'm having a similar issue, I picked a mower from the trash on our annual spring cleaning day. Mower had old nasty gas in it, a bad safety control cable and the air cleaner had pretty clearly never been changed. Took the carb all apart and sprayed it out with cleaner, got a gasket kit for it and put it back together. I got it started with some ether, but the governor was surging and it would only run on full choke. So I pulled it all back apart and ran it though the ultrasonic cleaner three times, then blew it all out with carb cleaner again. Reassembled, this time used some permatex on the gaskets. The surging is gone and it runs ok, but the mower still will not start without hitting it with ether. Spark is fine, plug was not too bad when I checked it and the gap was correct. The only thing I haven't done is check the valves, but it seems like ether wouldn't help if that were the issue.

Can't figure it out.

I'd check the valves and try again. Could be that or a loose head.

 

[slomo]

I'm having a similar issue, I picked a mower from the trash on our annual spring cleaning day. Mower had old nasty gas in it, a bad safety control cable and the air cleaner had pretty clearly never been changed. Took the carb all apart and sprayed it out with cleaner, got a gasket kit for it and put it back together. I got it started with some ether, but the governor was surging and it would only run on full choke. So I pulled it all back apart and ran it though the ultrasonic cleaner three times, then blew it all out with carb cleaner again. Reassembled, this time used some permatex on the gaskets. The surging is gone and it runs ok, but the mower still will not start without hitting it with ether. Spark is fine, plug was not too bad when I checked it and the gap was correct. The only thing I haven't done is check the valves, but it seems like ether wouldn't help if that were the issue.

Can't figure it out.

Boil clean the OEM carb. You need good heat to disolve that gunk in the carb.