[skellum]

I've searched and searched to find the following suggestions:

1. Adjust the valves (twin cyl, no ohv, not sure this engine has valve adjustments)
2. ACR broken (still trying to figure out if this has ACR or not)

Note: According the B&S IPL for this engine, there is no visible adjustment for the valves nor is there a compression release (when searched by name, compression is not found in the IPL document).

The mower belongs to my cousin and has been sitting for about 2 years. Rather than have it sit outside for an additional 10 years, I was hoping to fix it so they don't have to keep borrowing my mower. Enough backstory?

Rider: MTD
Motor Briggs & Stratton 16.5 Twin Cyl
Model: 42a707
Type: 2238 e1

-The motor will turn and start on "either" cylinder if the plug is removed from the opposite cylinder.
-Motor stops at compression stroke when both plugs are installed. (jumper cables from running vehicle to ensure power)
-Motor spins free when no plugs installed (duh!)
- removed both heads to verify there were no "stuck valves". (all "looks" well)

Feeling as if my head is against a brick wall (I've rebuilt chansaw motors, but never touched a B&S small engine before), I would like to ask for direction in finding/fixing this issue.

Thoughts?

[skellum]

Resolved by draining the crank case. Engine is now able to start.

[gilmorepink]

Hey skellum are you saying all you did was change the oil and it started? I have the same motor new starter just not enough power to crank even when on jumpers. Did you find if they have a decompression valve? And you are right the valves have no adjustment.

[DG]

The way you do the valve clearance is take them out and grind the ends until proper clearance is made.
And it does have a compression relief on the camgear.