Starting Problem

[Brads]

I'm hoping for a... most likely cause I guess. Got an older Murray Lawn Tractor this summer. 20hp B&S twin. It runs terrific but has a problem when turning over to start. It acts like the timing is off or at least that's what it reminds me of. Like when you advance the timing too far in a car and try to start it. It turns over and kinda hangs up in between each cylinder. Which of course is the spark plugs firing too soon. Now this engine runs off a magneto (right?) so I figured I'd check the flywheel and see if the shear key had broke maybe. Pulled off the big nut and looked but it was OK. So... anybody have a guess?

info. new battery this summer. Starter was froze from sitting (4 yrs) but after cleaning worked well. Could it still be bad? Maybe drawing too many amps? How would you check that? Ummm, battery cables?

Thanks

 

[Rivets]

You are going to have to adjust the valves. Post all the engine numbers and I should be able to find you a service manual.

 

[briggs]

as rivets said adjust the valves

 

[davbell22602]

If its vtwin briggs then manual part number is 273521. If its a Lhead twin then manual part number is 271172.

 

[Brads]

You are going to have to adjust the valves. Post all the engine numbers and I should be able to find you a service manual.

Adjust the valves. Super, I can do that. :smile: OK, I looked that up on youtube.com and the guy said to pretty much set all V-Twins to .004 thousandths. Does that sound right to you?

Here's the info. you requested:
Model 460777 25C
Type 1277 01
Code 9601155B
Briggs Diamond I/C
20 hp

 

[davbell22602]

Adjust the valves. Super, I can do that. :smile: OK, I looked that up on youtube.com and the guy said to pretty much set all V-Twins to .004 thousandths. Does that sound right to you?

Here's the info. you requested:
Model 460777 25C
Type 1277 01
Code 9601155B
Briggs Diamond I/C
20 hp

No, My briggs vtwin manual says .004-.006 for intake valve and .007-.009 for exhaust valve. Thats not a vtwin its Lhead twin.

 

[Carscw]

Here is a good guide to go by

 

[briggs]

Here is a good guide to go by

View attachment 18262

cool link :thumbsup:

 

[davbell22602]

Here is a good guide to go by

View attachment 18262

cool link :thumbsup:

But some of the info on there is not correct when comparing it to the Briggs manual for Lhead twins.

 

[davbell22602]

Here's link to the Lhead twin shop manual. http://dl.dropbox.com/u/12502267/B&S Service Manuals/02_271172TwinCylinderLHead.pdf