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Snapper Hi Vac compression question

#1

7

74eldo

Hey guys, I got this early 80's 3.5 hp Briggs and Stratton Snapper Hi-Vac a couple of weeks ago at an auction. Three mowers for 15 bucks, I figured I cant go wrong. The snapper fires with starting fluid but I have it in my basement so I cant run her on gas with out stinking up my house and it is quite the task getting her outside by myself. My question is will it run with only 50 psi? It seems a bit low to me, I would be happy with 60 psi but I am on the fence with 50 psi. Any thoughts on this? thanks!!


#2

M

mechanic mark

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#3

Hammermechanicman

Hammermechanicman

A "good" number is "it depends" engine has the easy spin bump on the cam so valve lash will make a difference in the compression reading besides rings and valves.


#4

B

Born2Mow

Sometimes on an engine that has sat for a look long while, the cast iron rings start to stick inside the piston. Using starter fluid, if you can simply get the engine to run long enough to get warm/hot and circulate some fresh 5W30 or 10W30 motor oil, then the rings will pop free and you won't even need to do any disassembly. If it ever starts, then let it run for 15 minutes minimum.

There are an equally long list of issues with carbs when people let them sit. So cranking may only end up pointing to bigger carb issues. But rebuild kits are cheaper for carbs than engines !!

For your greatest advantage, start with fresh fuel and a new plug, and the oil change. Hope this helps.


#5

VRR.DYNDNS>BIZ

VRR.DYNDNS>BIZ

see https://www.lawnmowerforum.com/thre...campaign=ed1543&utm_content=iss92#post-389783


#6

VRR.DYNDNS>BIZ

VRR.DYNDNS>BIZ

see post-389783


#7

7

74eldo

Born2Mow said:
Sometimes on an engine that has sat for a look long while, the cast iron rings start to stick inside the piston. Using starter fluid, if you can simply get the engine to run long enough to get warm/hot and circulate some fresh 5W30 or 10W30 motor oil, then the rings will pop free and you won't even need to do any disassembly. If it ever starts, then let it run for 15 minutes minimum.

There are an equally long list of issues with carbs when people let them sit. So cranking may only end up pointing to bigger carb issues. But rebuild kits are cheaper for carbs than engines !!

For your greatest advantage, start with fresh fuel and a new plug, and the oil change. Hope this helps.
Click to expand...
That's some good advise. Thank you!


#8

B

Born2Mow

I used the same tip on a mower that was in my BIL's junk pile. 15 min later and it's humming away in the side yard. It's going on CraigsList at the first sign of "green stuff" in the yard. This winter has gone by so slowly that I forgot what you call that "green stuff".


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