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

[bt3]

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

check for spark.if you have spark spray some starting fluid or carb cleaner in the plug hole and replace the plug if it pops but dies you got carb issues such as a clogged main jet.dont give up its worth the trouble new mowers are not like a duraforce.once you get in your groove its a snap to work on one

Absolutely. My next LawnBoy will be a Duraforce. Keeping an eye out for one in good shape. :thumbsup:

 

[dewguy1999]

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

I've decided that my Lawn-Boy has multiple issues, no-start and probably a carb that needs works. I've got a new fuel line and I'm waiting on the shut-off valve to fix the fuel leak due to the carb issues. My immediate problem though is the no start issue. I've twice previously checked for spark and confirmed that it did have spark, but my gut instinct after having replaced the CDI in 2007 is telling me to replace the CDI again, so I ordered one off eBay last night. Hopefully I'll get the new parts by the weekend and I get my overgrown lawn back in control. Short term I need a mower that I can get started and hopefully these two repairs will do that for me. Once that's accomplished I'll decide how to deal with the carb because I know long term that it needs to be dealt with. Guys, thanks for the encouragement, Lawn-Boys are great mowers and I want to keep this one going if I can.

 

[bt3]

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

On another thread I extolled the virtues of replacing the CDI on LawnBoys.
They have a reputation to fail, and when they are starting to fail, they mimic carb and fuel starvation issues.

There are threads on other boards that state you can sometimes breathe new life into a failing coil by baking it in an oven for 30 minutes at 185 degrees. I've tried this method with mixed results. Best to replace the coil. Amazon has coils (aftermarket) for 20 bucks that I find work very well. Sure beats 100 bucks for an OEM. For 20 bucks, I'd replace them first and ask questions later.

But yes, coils are always suspect on LawnBoys. When I hear "Bogging Down", or "Loss of Power", or "Stalling Out" or "Surging" I suspect a failing coil. It can be a carb issue of course, or governor or other issues, but you gotta' watch those damn LawnBoy CDI Coils! :thumbsup:

Keep us posted. Those of us that love LawnBoy want to know how it's going.

PS - I have found complete carb kits for my LB on Amazon. Just key in LawnBoy [part number]. I know Partstree is popular and that's fine, but I like Amazon because sometimes you have choices on whom to buy the parts from and at what price.

 

[dewguy1999]

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

On another thread I extolled the virtues of replacing the CDI on LawnBoys.
They have a reputation to fail, and when they are starting to fail, they mimic carb and fuel starvation issues.

There are threads on other boards that state you can sometimes breathe new life into a failing coil by baking it in an oven for 30 minutes at 185 degrees. I've tried this method with mixed results. Best to replace the coil. Amazon has coils (aftermarket) for 20 bucks that I find work very well. Sure beats 100 bucks for an OEM. For 20 bucks, I'd replace them first and ask questions later.

But yes, coils are always suspect on LawnBoys. When I hear "Bogging Down", or "Loss of Power", or "Stalling Out" or "Surging" I suspect a failing coil. It can be a carb issue of course, or governor or other issues, but you gotta' watch those damn LawnBoy CDI Coils! :thumbsup:

Keep us posted. Those of us that love LawnBoy want to know how it's going.

PS - I have found complete carb kits for my LB on Amazon. Just key in LawnBoy [part number]. I know Partstree is popular and that's fine, but I like Amazon because sometimes you have choices on whom to buy the parts from and at what price.

I read the other thread where you talked about replacing the CDI and I think it's good advice now that aftermarket CDIs are available at a more reasonable cost. The one I bought on eBay was "on sale" and was $18.00, the same seller also had them on Amazon Marketplace but was a couple of bucks more, so, I went with the one on eBay. I finally got an update on the shutoff valve that I ordered and according to tracking both it and the CDI will be here on Tuesday, hopefully the weather will cooperate next week and I get everything installed, the Lawn-Boy will start and I can give my rapidly growing grass a cut. Hopefully, I'll be able to let everyone know how it turns out next week.

 

[bt3]

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

Excellent Dewguy. We wish you luck. I'm sure you'll get that mighty Duraforce going strong again.

I don't do eBay because I've had huge issues with both sellers on eBay and with PayPal. Too long to post here, but my days of eBay are over. Amazon is more like Walmart. They don't balk at you needing a refund because you got a defective part, and you can use any credit card you like directly, without PayPal.

Have a good weekend with that great mower.

 

[dewguy1999]

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

Excellent Dewguy. We wish you luck. I'm sure you'll get that mighty Duraforce going strong again.

I don't do eBay because I've had huge issues with both sellers on eBay and with PayPal. Too long to post here, but my days of eBay are over. Amazon is more like Walmart. They don't balk at you needing a refund because you got a defective part, and you can use any credit card you like directly, without PayPal.

Have a good weekend with that great mower.

I've been using eBay for quite some time, but have mostly bought paperback books and a few other inexpensive items. I've had a couple of "hiccups" along the way, including this shut-off valve, but in the end all have turned out well. I don't think I'd ever buy anything expensive though.

Hope you have a nice Labor Day weekend as well.

 

[bt3]

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

Thanks.

Just yesterday, I started having issues again with the LB. My diagnosis was 80% CDI issue, 20% Carb. I always have a spare CDI on hand these days. Popped a new one on, and all was good 15 minutes later. Once you learn how these little monsters behave and you can diagnose things accurately, it's fairly straight-forward to fix them quickly and efficiently.

 

[dewguy1999]

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

Thanks.

Just yesterday, I started having issues again with the LB. My diagnosis was 80% CDI issue, 20% Carb. I always have a spare CDI on hand these days. Popped a new one on, and all was good 15 minutes later. Once you learn how these little monsters behave and you can diagnose things accurately, it's fairly straight-forward to fix them quickly and efficiently.

Wow, I guess I've had good luck with both of my CDIs lasting about 7-years. Both were OEM and I hope this new aftermarket one will last as long...or even longer.

 

[bt3]

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

Wow, I guess I've had good luck with both of my CDIs lasting about 7-years. Both were OEM and I hope this new aftermarket one will last as long...or even longer.

IMO, some of it has to do with engine cooling. The way the L21zsm is designed, the outer shroud and inner metal rim shield the CDI from some of the cooling, and I think the CDI really takes a lot of heat. I know they are designed to do so, but heat and time can wear on a CDI. Also, there were a batch of OEM CDI's that just plain were not very reliable, especially on F series engines. Combine the two and you've got a situation for CDI failure. Your Duraforce has a different design altogether, so it does not surprise me that your Ignition Coil lasted longer than mine do. But at 20 bucks a coil now via Amazon, I don't really care. If I had to replace one every season, I'd be OK with it.

Lawnboy coils are also more complex than many other lawnmower coils which may contribute to the failure rate. They are 2 stage. I can't remember the exact degrees (so don't hold me to this - I've got it written down in the shop). Starting coil stage is something like 8 degrees BTDC and after 800 RPM the running stage is something like 28 degrees BTDC. Again, I'm quoting that from memory, and have not looked at the actual figures in years. You can easily look it up online.

 

[dewguy1999]

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

IMO, some of it has to do with engine cooling. The way the L21zsm is designed, the outer shroud and inner metal rim shield the CDI from some of the cooling, and I think the CDI really takes a lot of heat. I know they are designed to do so, but heat and time can wear on a CDI. Also, there were a batch of OEM CDI's that just plain were not very reliable, especially on F series engines. Combine the two and you've got a situation for CDI failure. Your Duraforce has a different design altogether, so it does not surprise me that your Ignition Coil lasted longer than mine do. But at 20 bucks a coil now via Amazon, I don't really care. If I had to replace one every season, I'd be OK with it.

Lawnboy coils are also more complex than many other lawnmower coils which may contribute to the failure rate. They are 2 stage. I can't remember the exact degrees (so don't hold me to this - I've got it written down in the shop). Starting coil stage is something like 8 degrees BTDC and after 800 RPM the running stage is something like 28 degrees BTDC. Again, I'm quoting that from memory, and have not looked at the actual figures in years. You can easily look it up online.

It probably helps that here in Michigan it only gets used for about 6-months out-of-the-year and in my case, once a week where it only gets started once and run for about a half hour. I'm sure the minimal use helps to extend it's life.

It got me curious, so I looked it up in the Service Manual and in Lawn-Boy's own words, it's "about 5 degrees" BTDC and "about 28 degrees" BTDC at "about 800 RPM". You've got a pretty good memory.