Briggs Stratton............

[Goose]

We have a Poulan garden tractor with a 24 hp B&S engine. 320 hours on the meter. We don't use it to mow as much since we got a zero turn but it's still handy to have around.

Anyway, about a year ago a pushrod bent. I took the pushrod out and straightened it. Then I figured out the rear steel brake line on a Chevy pickup parts vehicle was a perfect press fit over the pushrod. I cut a piece of the brake tube about an inch shorter than the push rod and pushed the brake tube over the pushrod with about a half inch on each end. While reinstalling the push rod, I found the valve was stuck and I had to tap on the rocker arm to free the valve. Put it together and it ran fine-until today when it did the same thing with a different valve and pushrod.

I did my same bit with the piece of brake tubing. Then I figured while I had it apart, I might as well reinforce the other two pushrods for insurance. Found one of them with a slight bow in it. That one must be a slightly larger diameter than the first two 'cause the brake tube would not push over it. I straightened that one and put the whole works back together. It's running fine, now, for the time being. I just ordered two new pushrods online. I'll see what they look like.

Is this a known problem with the Briggs OHV engines? We had a 20 hp that went over 900 hours before we got rid of it and never had this problem. What would cause the valves to stick? Carbon on the stem?

I haven't talked to a dealer or a B&S tech yet.

Does anyone have any ideas?

 

[Janicholson]

Synthetic engine oil might be a solution. Jim

 

[kevinecwi]

Mine did about the same 24HP intek. Valve guides walk out of the head, limiting movement, equals bent push rod. Causes- engine running too warm, incorrect oil, poor design.
Fixed mine with a used head and push rods and now mix two stroke oil with gas hoping to lube intake valve stem better. Been good for almost 300 hrs now.

 

[504]

I have seen Kawasaki s do the same thing, push rods are cheaper than pistons and blocks.A little Marvel Mystery Oil might help too.

 

[Bob]

The pushrods bend 'cause the valves stick after a hot shutdown.

Running a quality synthetic oil (I use Mobil 1) simply eliminates the problem.

 

[josephmiller]

i work on some small engine stuff and i have heard and seen that polan are not very good eengines after not too many hours they break down, but they do work great for someon older that doesent do much but not for hard use every day. Like someone said i always put marvel mystery oil in and try to remember atleast once a month. it is cheeper than having a really bad messed up engine. if and when u get a new one i would first get a kohler, you need to care for it but they are really good engines if you are looking for power and good gas economy. briggs are good too they are a little less to watch but they are good long lasting engines but i think more goes wrong with them than others. hope this helps but hope you get your problem fixed

 

[johnlobb]

So I'm wondering guys, I have a B&S Intek 725cc engine with close to 700 hours on it and I have always ran synthetic oil. Do you think its a good idea to idle them for a while after running them hard in hot weather to maybe cool them down some?

 

[Txturbo]

(quoted from post at 03:07:21 08/21/15) i work on some small engine stuff and i have heard and seen that polan are not very good eengines after not too many hours they break down, but they do work great for someon older that doesent do much but not for hard use every day. Like someone said i always put marvel mystery oil in and try to remember atleast once a month. it is cheeper than having a really bad messed up engine. if and when u get a new one i would first get a kohler, you need to care for it but they are really good engines if you are looking for power and good gas economy. briggs are good too they are a little less to watch but they are good long lasting engines but i think more goes wrong with them than others. hope this helps but hope you get your problem fixed

ts a Briggs & Stratton engine, just like used in all other brands of mowers. If you add some Marvel Mystery Oil to it the problem will go away. The push rods are designed to bend on purpose so you don't punch a hole in a piston or break the head off the valve and destroy the motor.

 

[Geo-TH,In]

I've never bent a push rod, but heard some have. I read someplace the cause may be dieseling, engine running backwards, when you shut engine off.

Unlike most, I don't run my engines at 100% and never had dieseling on a briggs.

I have had dieseling on a kohler, so in the summer, I remover the ignition kill wire from switch. When I turn key off, it takes a few seconds for the solenoid in carb to shut off the gas and engine dies, no dieseling.

 

[Tom-NoCenTX]

Agree with others, below. Drain fuel tank, change fuel filter. Get fresh 93 octane gas, add Stabil at the 24 month storage rate, add Stihl 2-cycle oil at 1 to 200 ratio. Change motor oil and filter. Use Mobil One 10W30 full synthetic. Run at least one hour to full temp, let idle a minute or 2, as you hit the kill switch fully open throttle while it stops spinning and dies. Problems over. Tom

 

[showcrop]

(quoted from post at 03:57:27 08/21/15)

(quoted from post at 03:07:21 08/21/15) i work on some small engine stuff and i have heard and seen that polan are not very good eengines after not too many hours they break down, but they do work great for someon older that doesent do much but not for hard use every day. Like someone said i always put marvel mystery oil in and try to remember atleast once a month. it is cheeper than having a really bad messed up engine. if and when u get a new one i would first get a kohler, you need to care for it but they are really good engines if you are looking for power and good gas economy. briggs are good too they are a little less to watch but they are good long lasting engines but i think more goes wrong with them than others. hope this helps but hope you get your problem fixed

ts a Briggs & Stratton engine, just like used in all other brands of mowers. If you add some Marvel Mystery Oil to it the problem will go away. The push rods are designed to bend on purpose so you don't punch a hole in a piston or break the head off the valve and destroy the motor.

The refinery makes high quality tested and proven motor oil by removing part of the mineral oil, and you want to put it back in?

 

[Blackhole49]

You should let any engine cool down for a couple of minutes after running hard including your vehicles.

 

[rustyfarmall]

(quoted from post at 03:33:38 08/21/15) So I'm wondering guys, I have a B&S Intek 725cc engine with close to 700 hours on it and I have always ran synthetic oil. Do you think its a good idea to idle them for a while after running them hard in hot weather to maybe cool them down some?

I make it a practice when done mowing to shut off the blades, slow the engine down to idle, and slowly make my way back to the shed. By the time I am ready to stop the engine, it has cooled down as much as possible. If I finish up mowing somewhere close to the shed, I just make a couple of loops around the yard with the engine idling.

 

[Fred Werring]

Had one do the same thing.
I pushed the offending guide out, put 3 small dots of weld on the bottom edge of the guide, then cut shallow grooves on the OD of the guide and the ID of the head. Put some high temp jb weld on the guide and installed.

That was 2 years ago. Also started using synthetic oil. That guide has stayed put, and no other guides have walked out.

Fred

 

[GreenAcre]

I too add a little 2stroke oil to my gas not every tank but every few. Started after I had stuck valves in two different engines when the gas went to ethanol. Haven't had trouble again since started this and it's been a few years now.

 

[Goose]

Thanks for all of the responses. As far as I can tell, the guides haven't come loose, the valve stems just seized in the guides. Actually, both times it happened it was on a cold startup after it had run OK the last time it was used.

It can sit 'till I get the new pushrods. Then I'll install the new pushrods and change to oil to pure synthetic. Hopefully, I won't see the problem again.

 

[Rollie NE PA]

My 26 hp briggs did the same thing. I replaced one of the heads with a new one. One push rod is aluminum and one is steel. I add Marvel Mystry oil to each fillup. and have not had a problem in two years. Carbon on the stems is part of the problem.

 

[Anonymous-0]

(quoted from post at 11:07:24 08/21/15)

(quoted from post at 03:33:38 08/21/15) So I'm wondering guys, I have a B&S Intek 725cc engine with close to 700 hours on it and I have always ran synthetic oil. Do you think its a good idea to idle them for a while after running them hard in hot weather to maybe cool them down some?

I make it a practice when done mowing to shut off the blades, slow the engine down to idle, and slowly make my way back to the shed. By the time I am ready to stop the engine, it has cooled down as much as possible. If I finish up mowing somewhere close to the shed, I just make a couple of loops around the yard with the engine idling.

That's exactly what I do.