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I bought my current Lawn Boy (Model No. R7271) at a flea market in Indiana back in 1994. I have used the mower every season for mowing and the only maintenance I have performed year after year is regularly cleaning the accumulated grass off the under side of the deck, new plugs every few years, and sharpening the blade. While I probably should have done more, the mower has been trouble free for twenty years.

Earlier this year (at the start of the mowing season), my mower was hard to start (taking more than 4+ pulls to get it going) and it developed a gas leak when not running (if I forget to use the fuel shutoff). When running, it runs like a top. I called around and now that I live in California, I can't find anybody to repair my mower or to even perform a tune up. Apparently Californians don't like 2-cycles. I'm on my own.

I'm looking for some advice on where to start to look for the problem and any maintenance that I should do after years of "neglect." I found the lawn boy service manual online and I am willing to do anything on the mower. I have rebuilt car engines before, but the 2-cycle small engine world and the world of carburetors are new to me. Any advice, pointers, or starting points would be appreciated.

Thanks in advance!

The online manual is a good place to start. If you haven't dealt with two-cycles, read the section on two-cycle basics. The chapter on the fuel system will help with this problem.

The leak is most likely caused by the float valve -- it may not be sealing well.

Has the fuel been sitting in the tank since last year? If so stale gas (due to moisture form the air mixing with ethanol) could be the culprit. If the fuel is fresh and there's no dirt or gunk in the tank, fuel line or carb and it still is hard to start, come back here and ask.

BTW... :welcome:

You need a new needle and seat.It may not look bad but it usually is the culprit.Change all the carb gaskets too.

Thank you. Yes, the gas I have been using was left over from last season and this is the first time I have "over-wintered" my gas. I will try again this weekend with a fresh tank of new gas and see if that makes a difference. I'm hoping it is that simple, but I'll post back if I am still having issues. In the meantime, I will be sure to read the section you pointed out regarding 2-cycle engines. Thanks for the prompt response and welcome!

beg said:

You need a new needle and seat.It may not look bad but it usually is the culprit.Change all the carb gaskets too.

Click to expand...

Where is the best place to get these parts? When I asked around at the small engine repair shops in town, none seemed to have any clue where to get parts for my mower. I'm sure I can google around and look on ebay, but is there a place you all recommend?

Thanks!

I get most of mine on ebay or Parts Tree I get the parts number from parts tree and do a search on ebay with the part number under lawn mower parts and accessories the price is less on ebay for parts.Use only PREMIUM NON ETHANOL GAS

I've found that K&T Parts has very competitive prices and I think they have the float valve (needle and seat) that you need.

While your inside the carb,,,check the float to see if it's plastic it doesn't have fuel in it (leaking) , or cork it may be 'water logged'.

Jeff

I've used these guys. Good prices, fast and reasonable shipping.

Lawn Mower Parts, Blades, Accessories | LawnMowerPros

Good luck,

Jim

Replace both crank seals.

Thanks for all the replies. To close the loop on this . . . what a difference fresh (and real) gasoline make! The mower now starts up on the first (sometimes second) pull and runs great. When I have the time to watch it for leaks (this weekend), I will leave the fuel cut-off open to see if I still get a leak with the regular gas. At the end of the mowing season, I will likely overhaul the engine according to the wonderful suggestions here. It seems I need to rebuild the carb and replace the crank seals.

I just had the same issue with a m series I purchased.The carb was clean but the gas was old.engine would run a few seconds and die.had to flush out the tank with it on the mower as the screw that holds it in was stripped out.It runs great now.you may not need crank seals look for wetness around the bottom of the crank.that is the one that goes first.oh yeah ya gotta remove the blade and muffler.good time to clean the ports and sharpen the blade

2 places gas can leak. In the carb, with a bad float, needle and seat (easy replacement parts readily available). and the Fuel Shut-off. This uses a rubber gasket that over time takes a seat and will leak. This gasket is not available, AFAIK. Oh, and maybe old gas hose, which does not grip the nipples on carb and fuel valve tightly.

Hello yaknuts81, You can also purchase Lawn Boy parts at your Toro dealer if you have one near by.