Strange case of evil

[proximus26]

Hello all,

I have Bolen 158cc with B&S 10T800 series push lawn mower. Well I used it 6 year before I have noticed that it drop in power and start chocking.
I was sure all is OK (oil, gas,filter) so only things would be bad will be valve problem.

I was right, I have adjusted valves as per specification, put all back together and my engine want to fly. Started like a charm, no problem. Run for about 2-3 minutes during which I have check if all was OK.

Then I decided to change oil. I checked oil amount specification, I got 10w-40 oil and poor into engine. Prior that I have empty out old oil.

All, good. Decided to run baby again.... and I couldn`t turn it. I feel so strong resistance. I couldn`t start engine. Engine has high compression point where wont turn over.

I ask my self... what a heck. Let me check valves setting..., no all OK, springs OK. All is OK. Still can turn baby. Looks like oil pressure is building up and not allowing to engine in order to start.

I should mention that during intake valve removal on the valve I saw small o-ring with spring in side. i have check this part and is called Retainer-Valve. I assume that it was located on the same place as shown on the engine diagram.

So... engine started after adjustments. Engine is not working after oil change? I can turn engine with both hands but not with starter line?

Any idea what is wrong?

Thank you

 

[Rivets]

Many thing come to mind after reading your thread. First, Briggs does not recommend 10W-40 oil for their engines. I would replace it with straight 30W. Second, the O-ring you found is an intake valve seal. This keeps oil from being sucked into the cylinder. Third, how did you set the valves? This is what I would do.

1. Remove the spark plug from the engine and see if the engine will turn over by hand, not with the starter.
2. Check the valve adjustments again. If you need a manual, post all engine numbers and I will post one.
3. Replace valve seal.
4. Change oil.
5. Try turning engine over with starter, no plug.
6. Install plug and try starting.

 

[Mower Doctor 78006]

That sounds like the briggs classic style engine with the carb mounted on top of the gas-tank. over time the diaphragms dry out and cause a poor running condition. There about 4 bucks to replace. Its an L head engine. There's no valves to set. If you left the mower on its side and the carb drained in to crank case, pull spark plug and rotate mower blade by hand. That will clear out the hydro lock. Re install plug. It should run after that. That's why you can't pull the starter rope. Be sure you only use 20 Ounces of oil.

Hello all,

I have Bolen 158cc with B&S 10T800 series push lawn mower. Well I used it 6 year before I have noticed that it drop in power and start chocking.
I was sure all is OK (oil, gas,filter) so only things would be bad will be valve problem.

I was right, I have adjusted valves as per specification, put all back together and my engine want to fly. Started like a charm, no problem. Run for about 2-3 minutes during which I have check if all was OK.

Then I decided to change oil. I checked oil amount specification, I got 10w-40 oil and poor into engine. Prior that I have empty out old oil.

All, good. Decided to run baby again.... and I couldn`t turn it. I feel so strong resistance. I couldn`t start engine. Engine has high compression point where wont turn over.

I ask my self... what a heck. Let me check valves setting..., no all OK, springs OK. All is OK. Still can turn baby. Looks like oil pressure is building up and not allowing to engine in order to start.

I should mention that during intake valve removal on the valve I saw small o-ring with spring in side. i have check this part and is called Retainer-Valve. I assume that it was located on the same place as shown on the engine diagram.

So... engine started after adjustments. Engine is not working after oil change? I can turn engine with both hands but not with starter line?

Any idea what is wrong?

Thank you

 

[proximus26]

Many thing come to mind after reading your thread. First, Briggs does not recommend 10W-40 oil for their engines. I would replace it with straight 30W. Second, the O-ring you found is an intake valve seal. This keeps oil from being sucked into the cylinder. Third, how did you set the valves? This is what I would do.

1. Remove the spark plug from the engine and see if the engine will turn over by hand, not with the starter.
2. Check the valve adjustments again. If you need a manual, post all engine numbers and I will post one.
3. Replace valve seal.
4. Change oil.
5. Try turning engine over with starter, no plug.
6. Install plug and try starting.

Engine model is Briggs & Stratton 10T802-0018 550 Series Engine

I think this is correct model:158cc Briggs & Stratton Vertical Engine 10T802-0018-B1

I think you are right. I think valve seal might be a problem.

I have already changed oil to meet specification. Still same symptom. Valves were set incorrectly. I removed cylinder head and I could move them around like they never set correctly. I have adjusted valve and checked valve seat spacing, all was OK, as per manual.

I think missing valve seal might allowing oil to get into engine and this is why I can`t turn engine. Now this also explain why engine was smoking bad dark smoke... I guess one of seals failed at this point....

Should I order seals and valve or just valve seal only?

BTW I found this picture: http://www.amazon.com/Briggs-Stratt...&sr=1-6&keywords=Briggs+&+Stratton+valve+seal

I can tell that my part is broken because only top rubber part of this seal come out. This happen because I had problems to remove valve. maybe it was bend and during extraction destroyed this part of the seal.

I think this what I should change. How to replace this part?

OK< now I see where is engine number located on the engine. I will read correct model once I will be back home.

This small bugger give me more problems then my 2006 Jetta during timing belt replacement....


Thank you.

 

[Mower Doctor 78006]

Please explain how you set valves on an L head briggs engine??

Engine model is Briggs & Stratton 10T802-0018 550 Series Engine

I think this is correct model:158cc Briggs & Stratton Vertical Engine 10T802-0018-B1

I think you are right. I think valve seal might be a problem.

I have already changed oil to meet specification. Still same symptom. Valves were set incorrectly. I removed cylinder head and I could move them around like they never set correctly. I have adjusted valve and checked valve seat spacing, all was OK, as per manual.

I think missing valve seal might allowing oil to get into engine and this is why I can`t turn engine. Now this also explain why engine was smoking bad dark smoke... I guess one of seals failed at this point....

Should I order seals and valve or just valve seal only?

BTW I found this picture: Amazon.com: Briggs & Stratton 691963 Valve Seal Replacement for Models 805094 and 691963: Patio, Lawn & Garden

I can tell that my part is broken because only top rubber part of this seal come out. This happen because I had problems to remove valve. maybe it was bend and during extraction destroyed this part of the seal.

I think this what I should change. How to replace this part?

OK< now I see where is engine number located on the engine. I will read correct model once I will be back home.

This small bugger give me more problems then my 2006 Jetta during timing belt replacement....


Thank you.

 

[proximus26]

Please explain how you set valves on an L head briggs engine??

Well,

1. I have removed cylinder head. Put engine in top dead center (TDC).
2. I open side side for valves entry.
3. Measured space between end of valves and core support (I could not even enter 0.05 mm gauge meter). Then I have noticed that valves does not close properly.
4. I grind off end valve, measuring every time if they OK (install, remove, repeat).
5. Closed, fire up... works well.

Is something I did incorrectly?

Valve setting is something I need to do every 5k on my Yamaha Virago.

Problem is, as I mentioned one of valve seal come off, where other not. What I think this need to be replaced because seal was blow off (once I have start up engine) because was not attached anymore to mental ring I showed before (amazon picture).

 

[Mower Doctor 78006]

In all the years I have been around the L Head Briggs. I have never heard of the valves needing to be set. That's why I asked. Maybe one of the small engine experts can speak more on this matter.

Well,

1. I have removed cylinder head. Put engine in top dead center (TDC).
2. I open side side for valves entry.
3. Measured space between end of valves and core support (I could not even enter 0.05 mm gauge meter). Then I have noticed that valves does not close properly.
4. I grind off end valve, measuring every time if they OK (install, remove, repeat).
5. Closed, fire up... works well.

Is something I did incorrectly?

Valve setting is something I need to do every 5k on my Yamaha Virago.

Problem is, as I mentioned one of valve seal come off, where other not. What I think this need to be replaced because seal was blow off (once I have start up engine) because was not attached anymore to mental ring I showed before (amazon picture).

 

[Fish]

Yes, when an l-head overheats, the valve area warps away from the head, and the clearances becomes a problem.

I am having trouble wrapping my head around how "proximus" has adjusted his valves, kind of "Hinky"......

 

[proximus26]

OK,

here is exact engine model: 10T802-0547-b2 code 07100554

 

[Rivets]

Doing a valve job on a small engine has become a lost art. Back when small engines were commonly rebuilt, grinding and lapping in valves and seats were always done. The way proximus did it was one way of doing it. The only thing I would have done differently, is to recut the valve faces and seats, and lap the valves in before setting thevalveclearances. All my students had to know how to do it properly and it was part of their final test. Today the only time you need to gring a valve stem is when you are replacing the valve, or when you have to reseat a valve. To proximus; glad to hear that you were able to wade through the fishy posts and get the unit running.