Any small engine/lawnmower experts here?

[Freebird]

Here is the problem. Snapper zero turn. 21 HP Briggs Vanguard engine. Already run several tanks of gas through it this spring so it's not old gas. The problem just started the last time I mowed.

 

Backfiring bad through exhaust. Worse when I engage the blades and put a load on the engine. Worse as I give it more throttle. Starts easily.

 

Things I've done so far. New plugs, new air filter, Seafoam. None of which has helped at all.

 

Tomorrow I plan to check the valve clearance but I doubt that is the problem.

 

Any suggestions?

[buddy]

Here is the problem. Snapper zero turn. 21 HP Briggs Vanguard engine. Already run several tanks of gas through it this spring so it's not old gas. The problem just started the last time I mowed.

 

Backfiring bad through exhaust. Worse when I engage the blades and put a load on the engine. Worse as I give it more throttle. Starts easily.

 

Things I've done so far. New plugs, new air filter, Seafoam. None of which has helped at all.

 

Tomorrow I plan to check the valve clearance but I doubt that is the problem.

 

Any suggestions?

 

Rob my boss and best friend had the same issues your having and same motor. Had it looked over at the mower shop and found his valve push rods were bent cost him 86.00 for them to go in and replace them and one valve now it runs like a dream

The mechanic stated that once his motor back fired it bent the push rods which is common on these engines

[eusa1]

check pm on your phone don:detective:

[Kregerdoodle]

extra fuel tank is not centered over the rear axle! oh ..sorry wrong thread...

 

I really have no clue, probably a valve issue like has been said, does it have any kind of Vacum lines on it?

[Monty]

Bent pushrods are caused by the valve guides on the exhaust valves coming off their seat, and moving toward the outside. VERY common problem on these engines. When you pull the valve covers to check the valves, see if the guides have moved out, or if they are flush with the housing. You can call me, and I can explain it better & tell you how to fix it. 731-642-5091

[Freebird]

Buddy,

Yes, that is a real possibility. Those rods are aluminum of all things. I've already replaced them one time about two years ago. Very easy to do and there were no valves burned. I plan to check that tomorrow.

 

Eusa1,

Got your PM. Thanks. If I don't find a valve problem, that is the next thing I will check. Sounds like a big job though and I hope I don't have to do it.

 

This mower has just shy of 1700 hours on it now. I guess I can't complain but I know that when I bought it, I wished it had a Kohler or Kawasaki engine.

[Monty]

Two of the pushrods are aluminum. The other two are steel.

[Guest]

I seem to remember a zero turn mower being used as a chase vehicle driven by some speed demon from Chicago a few years ago. Maybe its just cowering in fear of another MD thrashing it may be put through......

[Squidley]

I seem to remember a zero turn mower being used as a chase vehicle driven by some speed demon from Chicago a few years ago. Maybe its just cowering in fear of another MD thrashing it may be put through......

 

Look something like this Jeff

[Freebird]

Those pictures just keep coming back don't they.

 

I think I have narrowed this down though. After taking to Eusa, I am betting that it's a sheared key on the flywheel. I broke a drive belt last weekend and finally got a new one delivered on Friday. Got it on and mowed about 3/4 of the yard before the backfiring started. When the belt broke last week, it got wrapped in the mower clutch and quickly bound everything up. It made a lot of noise and stopped the engine very quickly. Very likely that the key is sheared.

 

I'll pull the flywheel today and check it.

 

Thanks for all the responses.

[buddy]

Ok so you left out some info as to why it was back firing!

[Freebird]

Well, it turns out the the key in the flywheel was just fine. All the valves were a bit loose but not bad. I did find one of the rods appeared to be out of the seat a bit. None were bent. I lined all the rods back up, adjusted the valves and put it all back together. It seems to be running good again. I ran it full throttle and with the mower engaged and there was no backfiring. I won't call it fixed until I actually need to mow again. Raining here today though. I THINK it is OK now.

[saddlebum]

chances are when you pulled it apart you inadvertantly drained the pond water out of it. I suggest in future try using something other than your mower to cut down the weeds in the pond. Just who do you think you are anyway Yammer Dan

 

ps when checking for bent push rods don't just look at them roll them on a flat surface or down two straight bars supporting each end of the push rod. you can better see if the are bent or not.

[RandyR]

chances are when you pulled it apart you inadvertantly drained the pond water out of it. I suggest in future try using something other than your mower to cut down the weeds in the pond. Just who do you think you are anyway Yammer Dan

 

ps when checking for bent push rods don't just look at them roll them on a flat surface or down two straight bars supporting each end of the push rod. you can better see if the are bent or not.

 

Makes me wonder whether or not the repaired lawnmower lasted another 5 years?

[Freebird]

Well, it didn't last 5 more years. I replaced it this past summer. It was still running but smoking badly. I think, from what I could find out, that it probably had a warped head. It only smoked badly when you were turning.

 

At any rate, it was a residential mower with around 2600 hours on it. Pretty much worn out. I bought a new one and just recently sold the old Snapper to a retired gentleman who tinkers with and sells used mowers. He got it for $100.00.

[Yammer Dan]

How did I get in this discussion about Mowing grass?? The Warden is already wanting me to PLANT more grass!! I tried telling her the more Ya Plant the More Ya Gotta Mow!!! She don't seem to understand.....

[cowpuc]

How did I get in this discussion about Mowing grass?? The Warden is already wanting me to PLANT more grass!! I tried telling her the more Ya Plant the More Ya Gotta Mow!!! She don't seem to understand.....

 

That's cause you done created what is known as a negative vacuum with your, "gotta mow more comment" DanL.. Life has taught me that vacuum's are like most other things in life, there are positive vacuums (like the type used in making our V-4's run) and there are negative vacuum's like the one you inadvertently created with the lovely Warden.

I know you know enough about x4 carb vacuum's to make the V-4's hit on all 4 so I wont tell you all I know about those positive vacuum's but I think some study into negative vacuum's may be in order.. Not just for your benefit but also in a refresher course for your side kick up here in Michigan cause its almost time to ride and, for me anyway, that indicates a high probable time for producing negative vacuum's around here so,,, here goes..

Basically, this is how it works.. Anytime you or I remove, or even attempt to remove, any form of suggestion coming from those holding life and death over us or, in a lesser value, who hold final decision making power over us, we create a negative vacuum if we dont instantly and immediately replace the suggestive move with one of a higher esteemed value.. I know you know exactly what I am talking about but I probably should give an example of what I speak..

Example:

If, instead of stating that "planting grass creates more mowing" and thereby creating a negative vacuum that was sucking you towards lodging in that perverbial dog house,,, perhaps a comment like "I REALLY like the way you are thinking here Dearest Warden of mine and I can see where we need to get something over that dirt so mud quits finding its way into the house"... This first return comment is VERY important because it lets them (the Boss) know that we heard them and we think they are of superior intelligence and so on and so forth.. Next phase is what I call the "willing to spend" phrase and usually involves a little math.. Here is how it works:

You have cost out what seeding, planting, maintenance and so on will cost over the next 25 years and then build a cost comparison between that and covering the yard in 4 inches of concrete at this present time.. It is legal to use cost accounting and depreciation factors when doing this IMHO.. If needed for producing accurate sounding figures to put you over the top of proving the concrete will be the better value in the long run = any good MALE accountant can help with this..

Once you have gathered this info (some of our brothers successfully skip the above advanced method of creating positive vacuum and just spew out numbers but,, in your case as in mine DanL',, I STRONGLY suggest that you make sure your numbers jive BEFORE you produce them as I have a hunch "The Warden" is like Tippy and already on edge having been married to us for over 20 years) then it's a simple matter of presenting the upscaled, positive move comment that will create the positive vacuum that will fill the void in the best interest of both parties. I would say something like:

"Even with the added cost of the go carts to run around the go cart track on and fuel to operate them, at the 25 year interval we will still be $3600 ahead of the game and LOOK at all the fun you and I can have chasing each other around on the concrete while knocking any dirt/sand heading for the house off the track with the brooms I will tie wrap onto the back of the go carts".. Saying like that while your bolting a V-4 out of one of those Ventures in your garage into a recently built go cart frame with a little license plate on it that says "The Warden" on it is SURE to create positive vacuum!!

Hope this helps!!

Puc

[bongobobny]

Holy old thread, Batman!!!

[Yammer Dan]

I'm gonna Plant the Grass & keep my mouth shut!!!! That's a lot of concrete...........

[WildBill1]

[mraf]

Holy old thread, Batman!!!

 

:rotf: Mowing grass Shoveling snow:crying:. Riding Venture:big-grin-emoticon:. When is that Global Warming going to start?

[mraf]

That's cause you done created what is known as a negative vacuum with your, "gotta mow more comment" DanL.. Life has taught me that vacuum's are like most other things in life, there are positive vacuums (like the type used in making our V-4's run) and there are negative vacuum's like the one you inadvertently created with the lovely Warden.

I know you know enough about x4 carb vacuum's to make the V-4's hit on all 4 so I wont tell you all I know about those positive vacuum's but I think some study into negative vacuum's may be in order.. Not just for your benefit but also in a refresher course for your side kick up here in Michigan cause its almost time to ride and, for me anyway, that indicates a high probable time for producing negative vacuum's around here so,,, here goes..

Basically, this is how it works.. Anytime you or I remove, or even attempt to remove, any form of suggestion coming from those holding life and death over us or, in a lesser value, who hold final decision making power over us, we create a negative vacuum if we dont instantly and immediately replace the suggestive move with one of a higher esteemed value.. I know you know exactly what I am talking about but I probably should give an example of what I speak..

Example:

If, instead of stating that "planting grass creates more mowing" and thereby creating a negative vacuum that was sucking you towards lodging in that perverbial dog house,,, perhaps a comment like "I REALLY like the way you are thinking here Dearest Warden of mine and I can see where we need to get something over that dirt so mud quits finding its way into the house"... This first return comment is VERY important because it lets them (the Boss) know that we heard them and we think they are of superior intelligence and so on and so forth.. Next phase is what I call the "willing to spend" phrase and usually involves a little math.. Here is how it works:

You have cost out what seeding, planting, maintenance and so on will cost over the next 25 years and then build a cost comparison between that and covering the yard in 4 inches of concrete at this present time.. It is legal to use cost accounting and depreciation factors when doing this IMHO.. If needed for producing accurate sounding figures to put you over the top of proving the concrete will be the better value in the long run = any good MALE accountant can help with this..

Once you have gathered this info (some of our brothers successfully skip the above advanced method of creating positive vacuum and just spew out numbers but,, in your case as in mine DanL',, I STRONGLY suggest that you make sure your numbers jive BEFORE you produce them as I have a hunch "The Warden" is like Tippy and already on edge having been married to us for over 20 years) then it's a simple matter of presenting the upscaled, positive move comment that will create the positive vacuum that will fill the void in the best interest of both parties. I would say something like:

"Even with the added cost of the go carts to run around the go cart track on and fuel to operate them, at the 25 year interval we will still be $3600 ahead of the game and LOOK at all the fun you and I can have chasing each other around on the concrete while knocking any dirt/sand heading for the house off the track with the brooms I will tie wrap onto the back of the go carts".. Saying like that while your bolting a V-4 out of one of those Ventures in your garage into a recently built go cart frame with a little license plate on it that says "The Warden" on it is SURE to create positive vacuum!!

Hope this helps!!

Puc

 

Puc, Tip puts up with a lot doesn't she? But I like your thinking.

[RandyR]

Puc would have made a fine Shakespearean actor if he hadn't become a gear head.

[cowpuc]

Puc would have made a fine Shakespearean actor if he hadn't become a gear head.

 

,, To ride it or to fix it - THAT is the question

 

 

 

Puc's version of a Shakespearean actor: