Help: Lawn-Boy 21" SilverPro Series, 10247, DuraForce (2-cycle) behaving badly

[dewguy1999]

New member here. I have a Lawn-Boy 21" SilverPro Series Mower, 6.5 HP DuraForce engine (2-cycle), model number is 10247, purchased new in September 2000. In 2007 I was having starting problems and with the help of another forum I received advice and replaced the CDI. Well, after approximately 7-years it's having problems starting once again and I think it might need another CDI, but this time there may be other problems as well.

The last few years it seems to be smoking more at start up than usual as well as occasionally spitting something from the muffler (which I now believe to be fuel mix) but one/both symptoms stop once the engine warms up. I'm not positive but fuel may be going missing which I suppose my be due to the above. Tuesday I went out to clean the air filter which I haven't done in a number of years and realized that not only was there a patch of oily dirty stuff in front of the muffler, but the air cleaner housing, most of the engine from the cowling down as well as a good portion of the deck around the engine was also covered in this dirty stuff. I got most of it cleaned off, accessed the air cleaner filter, (which was amazingly cleaner than I expected considering everything on the outside) cleaned it, oiled it an replaced it. Some of this mess may have been my doing as I have overfilled the fuel tank a few times, but I think there may be something else wrong.

Yesterday, I went out to see if I could get it started and mow the lawn without any success. Due to it's inconsistent previous behavior I tried starting it without priming it, wouldn't start, tried priming it (3 presses) wouldn't start, tried priming it (3 presses) again with the same result of no start. Removed the plug and cleaned it, put it back and tried again still nothing. I did not check for spark yesterday, but it was producing a spark a few weeks ago when I checked it.

I don't really have any experience with internal combustion engines (2-cycle or otherwise) so I'm really in the dark as to what may be wrong. From what I've read on the net it sounds like it may be the carburetor or shaft seals (?) causing the fuel mess. Could this fuel leak (?) cause the starting problem or would it only be caused by the CDI failing? Is the OEM replacement CDI still the only choice or are there good 3rd party alternatives now?

Back in 2007 when I replaced the CDI it didn't have any other problems and the new CDI made sense but now I'm not sure it does. I'm now wondering if it makes sense to put on a new CDI or replace other engine parts on a 14-year-old mower (2000)?

Thanks.

 

[Phototone]

Re: Help: Lawn-Boy 21" SilverPro Series, 10247, DuraForce (2-cycle) behaving badly

Before you go replacing lots of stuff, determine if the mower still has spark. Take the spark plug out, attach the wire to the plug and ground out the outside of the plug to the engine head, away from the spark plug hole. Have someone squeeze the handle and pull the engine thru a few times. You should get spark. If not, then YES there are aftermarket Coils (CDI) available from many vendors and Amazon and Ebay that will fit your mower and cost about 1/2 what a OEM coil does.

 

[dewguy1999]

Re: Help: Lawn-Boy 21" SilverPro Series, 10247, DuraForce (2-cycle) behaving badly

Before you go replacing lots of stuff, determine if the mower still has spark. Take the spark plug out, attach the wire to the plug and ground out the outside of the plug to the engine head, away from the spark plug hole. Have someone squeeze the handle and pull the engine thru a few times. You should get spark. If not, then YES there are aftermarket Coils (CDI) available from many vendors and Amazon and Ebay that will fit your mower and cost about 1/2 what a OEM coil does.

Thanks for the reply.

Well, I went out and tried to start it tonight. Didn't prime it, just pulled the cord 3-4 times with no success. Took out the plug and checked it for spark and at least for the here and now it has spark. Put the plug back in and tried to start it, again without priming, started on the first pull, it smoked for a bit and then ran fine so I cut the grass. I looked at the deck after mowing and there was some fuel residue beneath the muffler (pics below) but I didn't see any elsewhere. So, now what?

 

[turfboy1997]

Re: Help: Lawn-Boy 21" SilverPro Series, 10247, DuraForce (2-cycle) behaving badly

Thanks for the reply.

Well, I went out and tried to start it tonight. Didn't prime it, just pulled the cord 3-4 times with no success. Took out the plug and checked it for spark and at least for the here and now it has spark. Put the plug back in and tried to start it, again without priming, started on the first pull, it smoked for a bit and then ran fine so I cut the grass. I looked at the deck after mowing and there was some fuel residue beneath the muffler (pics below) but I didn't see any elsewhere. So, now what?

View attachment 22725View attachment 22726

The needle and seat need to be replaced. part number 92-9697. Fuel is slowly leaking by the needle and seat and filling the crankcase and muffler up with raw fuel. Replace it and you should be good.

 

[dewguy1999]

Re: Help: Lawn-Boy 21" SilverPro Series, 10247, DuraForce (2-cycle) behaving badly

The needle and seat need to be replaced. part number 92-9697. Fuel is slowly leaking by the needle and seat and filling the crankcase and muffler up with raw fuel. Replace it and you should be good.

Thanks for the reply.

Are those carburetor parts? Is the leaking fuel causing the random failures to start?

 

[turfboy1997]

Re: Help: Lawn-Boy 21" SilverPro Series, 10247, DuraForce (2-cycle) behaving badly

yes they are inside the carburetor. the needle attaches to the float and the seat screws into the carb body. if you have spark its more than likely the carburetor needle and seat because it is flooding out making it hard to start.

 

[possum]

Re: Help: Lawn-Boy 21" SilverPro Series, 10247, DuraForce (2-cycle) behaving badly

Dang that Turfboy is smart. Do what he says. Or at least shut the fuel off every time when your done. Or both.

 

[turfboy1997]

Re: Help: Lawn-Boy 21" SilverPro Series, 10247, DuraForce (2-cycle) behaving badly

Dang that Turfboy is smart. Do what he says. Or at least shut the fuel off every time when your done. Or both.

the needle and seat is a very common problem with just about any carburetor. especially with the corrosion caused by ethanol in most gasoline. As for a fuel shutoff, duraforce mowers did not come with one stock. But you can go to lowes or home depot and buy one for 10 bucks.

 

[dewguy1999]

Re: Help: Lawn-Boy 21" SilverPro Series, 10247, DuraForce (2-cycle) behaving badly

yes they are inside the carburetor. the needle attaches to the float and the seat screws into the carb body. if you have spark its more than likely the carburetor needle and seat because it is flooding out making it hard to start.

Thanks. Since I drove old clunker cars when I was a teenager I understand the concept of flooding, but what makes this confusing to me is why it wouldn't and then would start yesterday when all I did was take out the spark plug and put it back in? Like I said in my original message I don't really have any experience with working on engines, so, I'm not even sure where the carburetor is, but, I'm assuming it's behind the air filter. From your description it sounds like replacing the needle and seat is going to require some disassembly, is that correct? How difficult is it to replace these parts?

Dang that Turfboy is smart. Do what he says. Or at least shut the fuel off every time when your done. Or both.

Thanks. As far as I know my mower doesn't have a fuel shutoff.

the needle and seat is a very common problem with just about any carburetor. especially with the corrosion caused by ethanol in most gasoline. As for a fuel shutoff, duraforce mowers did not come with one stock. But you can go to lowes or home depot and buy one for 10 bucks.

Thanks. I didn't know that ethanol was bad for mower engines. It's good to know that I haven't been overlooking the fuel shutoff all these years.

 

[beg]

Re: Help: Lawn-Boy 21" SilverPro Series, 10247, DuraForce (2-cycle) behaving badly

Install a 1/4 inch right angle fuel shutoff and your problem will be solved.you can replace the needle and seat too but try the shutoff valve first and see what happens.Thank you for cleaning up your mower.gook and grime retains heat and warps the carb body