First, I read many posts on this site both now and in the past, and appreciate everyone's input.
I have a Briggs and Statton 12.5 HP (Model 28V700 Type 1170) on a Riding Tractor. I purchased the tractor used a few years ago and have been using it without major issues since then, except for minor repairs such as a bad tire, blade maintenance, and repair to the steering system. Last fall, before winter in Ohio hit, I put in some gasoline stabilizer. About mid-winter around late January, I took the mower out on a warmer day and it started instantly and I let it run for about 5 minutes. Later in the early spring, I took it out again, and again it started right away and I let it run another 5 minutes or so. I put it back in the garage and there it sat for a month or so as I had repairs done on the garage door. I mowed (and mowed and mowed) the lawn with a small electric mower that I had that I could push out the garage pedestrian door. Once the main garage door was working, pushed the riding mower out and started it up, again right away, and mowed the front yard. I was about half-way through with the backyard when the engine died. There were no loud noises, it just sort of sputtered and stopped. I checked and saw it was almost (if not totally) out of fuel, so I got some fresh gas and put some in. The lawnmower has not worked again, despite my many attempts to get it going. Some things have changed the lawnmower's actions a bit, but nothing has gotten it running again. The main complaint is that the mower sounds like it is trying to start. It turns over and occasionally seems to run a fraction of a second, then sputters again. At first, the mower backfired both through the exhaust and intake at times, but only if I fiddled with the throttle and choke a bit.
Here is an outline of what I have tried:
1. Added fresh gas -- No change
2. Checked Spark Plug -- Very gassy smell and wet with gas. Plug not bad otherwise. Gasoline pooled in bottom of air filter housing.
3. Removed and cleaned Carburetor (assuming float was stuck) -- Also cleaned choke linkage and throttle control linkage -- No change -- Less fuel in filter housing.
4. Pulled flywheel and checked shear pin -- Pin okay, no looseness in flywheel. Cleaned magneto coil and rotating magnets -- No change, but spark looks better.
5. Changed air filter -- No change. Removed air filter completely to see if unlimited air would help with apparent flooding -- no change (filter back on)
6. Replaced carburetor with new unit sealed in box from Garage Sale -- Fuel not pooling in air housing as much -- only after extended cranking. Backfires only when key first turned, then just sounds like it may start but doesn't. I keep thinking there is way to much fuel and not enough air to get combustion. Fuel would evaporate some after sitting and might explain the backfire initially, but once too much gas got past carburetor, no amount of turning engine over would let it start.
7. Starting Ether sprayed into the carburetor had no effect when I tried it around step 2 or 3. This and the fact there was standing gas in the inlet made me think the problem was the carburetor, but a rebuild and replacement had no major effect.
I am now wondering if inlet valve is stuck opened, or if major "timing" issue may be an issue due to crank shaft being twisted or something. I plan to check the compression if my gauge fits this sparkplug hole. I am about 99 % sure I did not hit anything when engine first stopped, although I have hit a few things over the years, but the engine kept running. There was an appreciable amount of dirt and dried grass on the engine when I first bought it -- almost a cement like consistency, but I cleaned it off the first year. I have no way of knowing what else might have happened to the machine when the first owner(s?) had it. I purchased it at a charity thrift store, and figured it might have some issues, but since I have used it for years, I figured I had lucked out.
Any suggestions or comments would be appreciated. While I have not taken the head off a small-gas engine like before, I have done this with several auto engines over the years. I am somehow keeping up with the lawn mowing with my electric, but really would like to get the lawn tractor back on its wheels to save time.
Perry
I have a Briggs and Statton 12.5 HP (Model 28V700 Type 1170) on a Riding Tractor. I purchased the tractor used a few years ago and have been using it without major issues since then, except for minor repairs such as a bad tire, blade maintenance, and repair to the steering system. Last fall, before winter in Ohio hit, I put in some gasoline stabilizer. About mid-winter around late January, I took the mower out on a warmer day and it started instantly and I let it run for about 5 minutes. Later in the early spring, I took it out again, and again it started right away and I let it run another 5 minutes or so. I put it back in the garage and there it sat for a month or so as I had repairs done on the garage door. I mowed (and mowed and mowed) the lawn with a small electric mower that I had that I could push out the garage pedestrian door. Once the main garage door was working, pushed the riding mower out and started it up, again right away, and mowed the front yard. I was about half-way through with the backyard when the engine died. There were no loud noises, it just sort of sputtered and stopped. I checked and saw it was almost (if not totally) out of fuel, so I got some fresh gas and put some in. The lawnmower has not worked again, despite my many attempts to get it going. Some things have changed the lawnmower's actions a bit, but nothing has gotten it running again. The main complaint is that the mower sounds like it is trying to start. It turns over and occasionally seems to run a fraction of a second, then sputters again. At first, the mower backfired both through the exhaust and intake at times, but only if I fiddled with the throttle and choke a bit.
Here is an outline of what I have tried:
1. Added fresh gas -- No change
2. Checked Spark Plug -- Very gassy smell and wet with gas. Plug not bad otherwise. Gasoline pooled in bottom of air filter housing.
3. Removed and cleaned Carburetor (assuming float was stuck) -- Also cleaned choke linkage and throttle control linkage -- No change -- Less fuel in filter housing.
4. Pulled flywheel and checked shear pin -- Pin okay, no looseness in flywheel. Cleaned magneto coil and rotating magnets -- No change, but spark looks better.
5. Changed air filter -- No change. Removed air filter completely to see if unlimited air would help with apparent flooding -- no change (filter back on)
6. Replaced carburetor with new unit sealed in box from Garage Sale -- Fuel not pooling in air housing as much -- only after extended cranking. Backfires only when key first turned, then just sounds like it may start but doesn't. I keep thinking there is way to much fuel and not enough air to get combustion. Fuel would evaporate some after sitting and might explain the backfire initially, but once too much gas got past carburetor, no amount of turning engine over would let it start.
7. Starting Ether sprayed into the carburetor had no effect when I tried it around step 2 or 3. This and the fact there was standing gas in the inlet made me think the problem was the carburetor, but a rebuild and replacement had no major effect.
I am now wondering if inlet valve is stuck opened, or if major "timing" issue may be an issue due to crank shaft being twisted or something. I plan to check the compression if my gauge fits this sparkplug hole. I am about 99 % sure I did not hit anything when engine first stopped, although I have hit a few things over the years, but the engine kept running. There was an appreciable amount of dirt and dried grass on the engine when I first bought it -- almost a cement like consistency, but I cleaned it off the first year. I have no way of knowing what else might have happened to the machine when the first owner(s?) had it. I purchased it at a charity thrift store, and figured it might have some issues, but since I have used it for years, I figured I had lucked out.
Any suggestions or comments would be appreciated. While I have not taken the head off a small-gas engine like before, I have done this with several auto engines over the years. I am somehow keeping up with the lawn mowing with my electric, but really would like to get the lawn tractor back on its wheels to save time.
Perry