Some one was kind enough to give me a Craftsman Lawn Mower (used) as my son is now able to mow the lawn. The mower has a 6.5 hp Briggs and Stratton engine. When I poured the oil out to change it, there was very little in the crank case and it was black. The Carborator bracket is broken and the engine housing cover also needs to be replaced. Point being, for about $70 in parts, I can fix what I can see what is wrong with it. I used a compression gage, turned the engine backwards several times with a socket wrench and it is holding 55 psi overnight.

The Model for the Briggs engine is 125K02, Type 0273.

Can you please advise me in I should spend money fixing this up? Can you tell how old it is?

John

 

Hello John!

55 psi overnight? Are you sure the compression gague hasn't got a schraeder valve in it and the gague itself is not what's holding that reading? It's pretty much impossible for the cylinder to hold pressure for more than a few seconds, even in a new engine.

On this particular engine, I would not spend any money on it until I got it running well enough to determine if it is smoking or knocking. These are prone to bad cylinder wall scoring and smoking. If you cannot get it running without spending some $$, then I would at least pull the head and check the cylinder walls. Unless it has a cast iron sleeve, I bet it has scored cylinder walls, especially since it was low on oil. Good chance it has a bit of rod knock too. Also, check the crankshaft to be sure it's not bent. Look at the carburetor bracket. Is there a mounting bolt missing behind the carburetor where the bracket mounts to the block? If so, check the bolt hole. They commonly break off, leaving the broken end in the hole in the block.

 

Cheese,

Thanks for the heelp. Is 55 psi close to something acceptable? I will put it back together and see if I can get it running.

I have never gone into an engine before, so this may be a learning experience for me as I explore if I need to.

I will let you know (as soon as the garage warms up!)

John

 

Compression readings on small engines are'nt reliable. There are too many variables. If I saw 55psi on a gague, I would at least be satisfied that it should have enough to start and run. Other than that, it's a toss up.

 

Cheese,

I got it back together and got it started. runs poorly and smokes a lot. Seems that the 55psi overnight was a function of me not knowing how to use the gauge.

Should I think about a rebuild or scrap it?

John

 

Sorry to hear that. You could pull the head for fun and see how the cylinder walls look. If they're in nice condition, then it might be worth installing a new set of rings. Otherwise, I'd scrap it or donate it to a high school auto or small engine class.

 

Thanks Cheese