HELP, I need a Briggs & Stratton "EXPERT"!

Bill Lewis · 2004-04-11T20:14:30+00:00

I borrowed a friend's 2 man post hole auger (General Model 70). Sortof a semi-permanent loan. He's got no place to store it. It's got a5 hp Briggs and Stratton Vertical shaft engine (model 130920, type0382, build date is 6/8/76). When I got it home it was obvious thatthe engine hadn't been run in awhile, and the whole thing appears tohave very few hours on it.I am having trouble keeping it going. Below is a list of what I havedone so far. This list is not necessarily in exact order, regardlessof what I have done so far, the basic problem persists. I can coldstart it and run it under no load or with a load and it seems to runfine, but after using it for about 5 minutes (under load), it startsto die (surging). If I choke it quickly, I can get it to keep goingoff and on for maybe a minute or two more, but it ultimately diesout. It will do the same under a no load condition, but it seems to take ita bit longer to occur. Not much mind you, and this may only be myperception of time.I have been running it without an air cleaner, but with the aircleaner screw in place. I have a new foam air cleaner on back orderat a local shop. I'm not using it in a dusty condition, (been toodamp) so I'm not really worried about dirt.I'm at a loss at this point. I really need an experts advise on thisone. Right now, my thumbs are killing me from running a one-man(manual) post hole digger.List of "repairs" to date:Replaced spark plug (original RC-J8 was still in it) with a C-J8.Same heat range plug, just not resistor. Though the original stillruns it as goo (or bad) as the new one.Added a screw-in straight pipe generic muffler (original wasnon-exsistant).Removed and cleaned tank-mounted (pulsa-jet) carburator. Replaceddiaphram, and main fuel pickup tube. I also put some carb cleaner inthe tank, and a bunch of nuts and bolts and shook it for quite awhileto clean it. Then flushed it with clean fuel. It takes it about 3 turns out on the needle valve to make it run thebest (by...

Apr 11, 2004 24 Replies

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Walt Conner 22 years ago

Small B&S engines use an easy spin cam grind which depends on proper valve clearance to work, also, excessive valve clearance adversely affects engine breathing hence, performance.

All aluminum block, flat head B&S engines that I am aware of, call for .005 - .007 for intake and .007 - .009 on smaller engines .009 - .011 for larger engines for exhaust clearance.

The old cast iron block B & S engines did call for clearances .007 - .009 for intake and .017 - .019 for exhaust.

You are right that one cause of dying after a few minutes of running is not having enough valve clearance.

Walt Conner

course years ago. I've found >they work nicely.

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Randd01 22 years ago

He said the enigine is like new. How could he have lost valve clearence unless the seats or valve faces got beat out?

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m Ransley 22 years ago

OP said motor was like new but compression was 65lb . Well 65 lb makes it probably a 1 hp junk, worthless unless he put it back together wrong.

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Walt Conner 22 years ago

I have seen brand new B&S engines come from the factory with not enough valve clearance. I made one heck of a buy on a riding mower once because the dealer couldn't figure out why the engine kept dying after several minutes of running. He took it back from an unhappy customer, don't know why he didn't replace the engine under warrantee but I didn't care.

Walt Conner

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Randd01 22 years ago

Interesting thanks

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