# compression for Briggs



## Rentahusband (Aug 25, 2008)

What should the compression on a 5hp Briggs be? Model 130202.
Thanks


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## 30yearTech (Sep 14, 2006)

Briggs does not publish compression readings for their engines. Their general rule of thumb is to spin the engine over and as it winds down the flywheel should either come to an abrupt stop or bounce backwards. If it just slows to a stop, then compression is too low.

Most "L" head Briggs will start and run with around 50 lbs of compression. An engine in good condition I would expect to have a reading of around 90 lbs.


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## Rentahusband (Aug 25, 2008)

Thanks. It tested around 65-70psi. Just wanted to have a range before I went any further. Has been sitting for awhile, no spark. So I am guessing points/condensor may be bad.


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## duffer72 (Jul 23, 2011)

unless it is almost 30 yrs old you have no points in it, if code on engine #s start with 83 or higher you have magnetron ignition in it,


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## Rentahusband (Aug 25, 2008)

Well, it must be around 30yrs old it has points. I do not see a spark on the plug but I do feel current at the plug wire. Yes, I used a new plug.


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## phillipmc (Jan 27, 2008)

Alot of times just cleaning the points and resetting the gap to .010 fixes the issue. You can get a kit that converts the ignition to electronic. for about $12 max


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## 30yearTech (Sep 14, 2006)

phillipmc said:


> Alot of times just cleaning the points and resetting the gap to .010 fixes the issue. You can get a kit that converts the ignition to electronic. for about $12 max


Point gap for Briggs engines is .020"


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## shoes (Nov 17, 2009)

*low rpm at high throttle*

have an briggs 18.5hp intek ohv single cyl. starts fine has good idle speed. when goin to high throttle has low rpm like timming is off no power. i checked the clearance on vlaves with in specs .oo4-.006. i noticed the intake valve closes then pops back open n closes. thats seems strange thought normally valves stays closed. has any one ran into this situation of no power at high throttle. this is an first for me. any assistance will be appreciated tks


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## 30yearTech (Sep 14, 2006)

shoes said:


> i noticed the intake valve closes then pops back open n closes. thats seems strange thought normally valves stays closed. has any one ran into this situation of no power at high throttle. this is an first for me. any assistance will be appreciated tks


What you are describing sounds like the compression release. The valve (and it can be either the intake or exhaust), opens momentarily on the compression stroke to reduce the cranking effort for the engine. Once the engine is spinning above cranking speeds, this action stops.

Check for either a dirty air filter element, or possibly a sticking choke on the carburetor. I run across many of these engines where the choke shaft swells and does not move freely in the carburetor, this usually prevents the choke from opening back up all the way. When this happens, you get little to no power and low top speed rpm's.


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## shoes (Nov 17, 2009)

tks 30rys for the reply........air cleaner is new, choke is working okay......spark is good, runs like when muffer is plugged, or retarted timming... diconnected muffler it still ran the same.......tried another carb and coil, same results darn thing just doesn't rev to high speed iam stumped.........


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## duffer72 (Jul 23, 2011)

Did you check the flywheel key, it may be partialy sheard, have seem it happen on a few riders over the years.


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## 30yearTech (Sep 14, 2006)

Well I would do as duffer suggested, but if you find the key to be good, then I would suspect the problem is with the camshaft. 

I have run across some of these engines, where the lobes on the camshaft wore down and caused an issue similar to what you are describing.


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## shoes (Nov 17, 2009)

found out the problem the intake valve is only opening about 1/16 of an inch, the exhaust goes about 3/16.......suspect camshaft is the problem. will check that out. tks for all the input, i did check the flywheel key its okay duffer72.......appreciation all the assistance


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## Rentahusband (Aug 25, 2008)

New points/cond/diaphram and the old thing purrs like a kitten. Owner was happy.


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