Briggs&Stratton Powerbuilt 3130, 344cc, Low power

P

Per_XXX

Forum Newbie
Hi

from one day to next day, the power was dramatically reduced. Something broken i guess, not just getting "old".
I have checked the spring on the governer and the valve clearance without result.

But when looking at how the valves move when turning the engine I might have something.
The upper valve (exhaust i guess) move as expected.
The lower valve moves less and has a "dubble jump.
Damaged camshaft?

Any ideas or suggestion what to check?
 
Thanks for comment. Something like that was my guess too.
The strange thing is that it came very suddenly.

What do you think, risk for damages of other parts inside the engine?
 
The issue is the hardening of the cam lobe. It wasn't properly hardened therefore when the small amount of hardening wore through the rest of the lobe is very soft and would wear down quickly. also even if it was slowly wearing down, most people wouldn't notice the small changes until it hit a point of notice, which appears to have started suddenly and in reality has been happening over 50 hours..

I don't think there is much concern about damaging other parts since the compression release seems to be operational. that would be my major concern if those pieces were laying loose in the engine.
 
ILENGINE said:
The issue is the hardening of the cam lobe. It wasn't properly hardened therefore when the small amount of hardening wore through the rest of the lobe is very soft and would wear down quickly. also even if it was slowly wearing down, most people wouldn't notice the small changes until it hit a point of notice, which appears to have started suddenly and in reality has been happening over 50 hours..

I don't think there is much concern about damaging other parts since the compression release seems to be operational. that would be my major concern if those pieces were laying loose in the engine.
Click to expand...



Thanks for support:)
I will take the engine apart and see what it looks like.

The compression release, is that integrated in the camshaft or is it a separate component?
When I look for camshafts to B&S they look "rather normal" without anything extra.
 
Per_XXX said:
Thanks for support:)
I will take the engine apart and see what it looks like.

The compression release, is that integrated in the camshaft or is it a separate component?
When I look for camshafts to B&S they look "rather normal" without anything extra.
Click to expand...
It is part of the camshaft. It is the part next to the gear in this picture 1788708978755.png
and the shaft in the center
 
ILENGINE said:
Intake lobe worn down to almost round with a working compression release. Looking at new camshaft.
Click to expand...
Some feeedback. You were right. :)
Its a miracle that it worked at all. Almost round.

But what surprised me was that it looked as if the engine had ben opened before. I thought this engine was "sealed for life". I do of course not know what was done but i must have been for a good purpose. Are camshafts typical weak components?
 

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Per_XXX said:
Some feeedback. You were right. :)
Its a miracle that it worked at all. Almost round.

But what surprised me was that it looked as if the engine had ben opened before. I thought this engine was "sealed for life". I do of course not know what was done but i must have been for a good purpose. Are camshafts typical weak components?
Click to expand...
Compression release breaks are well documented on the single Intek OHV engines. And I have seen maybe 1/2 dozen lobes wear round over my 28 year career on both the single and twin cylinder engines.
 
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