Need help, 5 HP Briggs, circa 1986

N

NauticalNaturist

New Member
#1
#1
I just bought a circa 1986 Troybilt Pony tiller with a Briggs 5 horse Model # 130212 0512-01, not running, no compression. Lapped the valves, reset to ,oo6 and .010 inches. New rings (gaps around .015", not ideal but better than originally), piston and rod. Lapped the head and block. I still only have 5lbs compression. I also have a slight amount of compression leak through the carb. Rechecked the intake lash, still .005. The engine did not appear to have been opened before I got it so I do not suspect a cam problem, yet I have the pressure through the carb and essentially not compression.
Thanks guys
 
sparkwizard

sparkwizard

#2
#2
Did you have the cam out? Did it go back in correctly?
Did you install a copper head gasket?
There is a compression release built into the cam. I do not know what your compression reading should be, but the compression release does leak air out the intake side.
 
N

NauticalNaturist

New Member
#3
#3
sparkwizard said:
Did you have the cam out? Did it go back in correctly?
Did you install a copper head gasket?
There is a compression release built into the cam. I do not know what your compression reading should be, but the compression release does leak air out the intake side.
Click to expand...
Thanks for the quick reply.
The cam went back in correctly, punch marks on the crank gear and cam gear lined up. The gasket kit came with a new metal head gasket, may be copper.
No compression release on this old (1985?) five horse.
I reset the intake valve clearance to almost .008. I now have 35-40.lbs compression. Still low but I will try it.
 
sparkwizard

sparkwizard

#4
#4
There is an irregular cam lobe on the intake side of the cam. It keeps the intake valve open just a crack while the piston is on its way up on the compression stroke. It really annoyed me earlier this year, when I had the same problem you have now. I was advised that it would not effect performance once it got running.
Have you tried to start it? Evidently, they do not leak so bad once they get spinning faster that rope-pulling speed.
I ground my valve and opened up the clearance enough to defeat it.
 
N

NauticalNaturist

New Member
#6
#6
OK an update on my 5 horse Briggs.
It will run if I drip gas into the intake. I added some SeaFoam to the tank gas and got it to run, but only on full choke. I should get my carb rebuild kit the first of next week.
The engine smokes like a diesel. Looking over the engine I found a LOT of black oil on and coming from the muffler, running down the engine. I checked the new rings and found I have about .015 clearance about halve way down the bore. More than ideal but better than the .030-.045 I had before. The oil ring was slightly more. Is excess ring gap my problem? Short of boring the block is there any cure?. I may just run it till I can buy a new engine.
Thanks
 
creia

creia

#7
#7
NauticalNaturist said:
OK an update on my 5 horse Briggs.
It will run if I drip gas into the intake. I added some SeaFoam to the tank gas and got it to run, but only on full choke. I should get my carb rebuild kit the first of next week.
The engine smokes like a diesel. Looking over the engine I found a LOT of black oil on and coming from the muffler, running down the engine. I checked the new rings and found I have about .015 clearance about halve way down the bore. More than ideal but better than the .030-.045 I had before. The oil ring was slightly more. Is excess ring gap my problem? Short of boring the block is there any cure?. I may just run it till I can buy a new engine.
Thanks
Click to expand...
Are the valve guides excessively worn? (VERY common on old Briggs engines with a lot of use.) If so, oil will be sucked up from the valve spring compartment up through the valve guide and into the cylinder head.
Michael
 
N

NauticalNaturist

New Member
#8
#8
This engine seems to have low hours on it, as does the TroyBilt Pony tiller it came on, despite being a 1985 model. The valve stems seem to fit as well as any I have seen. The valves seemed to lap easily, without any wobble or slop. I am not very concerned about the guides. It is quite evident the engine had an oil leak before I got it and the new piston and rings did not help. My "sump" (bearing plate?) gasket was sealed with gasket maker and the paper gasket so I do not suspect that joint.
Do my ring gaps seem excessive enough to pull oil through the cylinder?
 
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