Sure. First thing to check is carboned-up exhaust ports in the cylinder and clogged muffler. Next you have to check the crankshaft end seals. You expect to see oil build-up to some extent around them but not raw fuel. The 2-cycle engine must have a sealed crankcase because it is 'self-charging'. When the piston goes up, it draws fresh fuel/air in. When the piston comes down, it compresses the mixture which then 'escapes' into the cylinder as the piston uncovers a port in the cylinder wall.
Let us know what you find. You're not going to get it running without getting dirty.

Thanks for the response, saxman.

Yeah I forgot to mention that I did check the exhaust port and there wasn't very much carbon buildup. I also notices the piston and cylinder wall were perfectly clean with no buildup so I don't think that's a problem.

I was worried that it might be the crankshaft seals and if it is that might be more work than I want to put into this mower since it's over 20 years old. How do I gain access to them so I can at least look at them and see if they are leaking bad? I was thinking it might be harder on this model since it has a blade clutch.

In the meantime I think I'll do what I said before and check the fuel filter and fuel lines and make sure they aren't clogged/cracked, since that is an easy check.

Thanks for the help

I wonder if it might have a clogged fuel cap? Sometimes they do get stopped up which stops the gravity fuel flow. You might temporarily, and for testing only, loosen the cap when it starts to mess up and see if it keeps running. Don't use it with a loose cap for safety reasons - that's a fire looking for a place to start. If its the cap you might be able to clean it.

Although crank seals have been known to leak on Suzuki 47P engines, they exhibit almost the opposite symptoms. The engine will be very difficult to start, but once running, then sounds OK. Replacing the seals requires splitting the cases and removing the cylinder, which is not a "shade tree" job. The seals themselves are relatively inexpensive. The 81-0720 upper is about $8 and the 81-0740 lower is about $10.

I think you have carburetor problems. The Mikuni carb fitted to the Suzukis is prone to clogging, and is difficult to clean. There are several hidden passages, and even a prolonged soaking in industrial strength carb cleaner won't always work. The spray-on stuff is useless, and fuel additives like Sea Foam, while good, won't help a bit if a passage is clogged. Unfortunately, a new carb runs north of $200.

Suggest you tear down the carb, remove everything that isn't metal, and then buy a good carb cleaner with dip basket like Berryman's B12 or Gunk CC3K. Soak for several days, and even better if you have an ultrasonic cleaner. Figure one or two hours ultrasonic.

I finally got around to working on this mower again and took the carb off and cleaned everything out with carb cleaner and blew compressed air through all of the jets and orifices and made sure everything was clear.

I put it back together and ran it with the blade disengaged and it ran great for about 30 seconds. Then it idled down for a second before speeding up uncontrollably to the point that it sounded like it was gonna blow up. I quickly reduced the throttle and engaged the blade to slow the engine down. Then I went to test it out and like before, after running for a little bit with a load on the engine, it dies.

It will run as long as you want with the blade engaged and stationary, but if you try to mow with it it dies after only about 30 seconds of mowing. I also noticed that when the blade is engaged the engine speed is fine, but if you disengage the blade, it revs way up.

I noticed that if I turn it off when the engine starts to rev way up, then restart it right away, it will run fine again for about 30 seconds, then rev way up again. I can repeat as many times as I want. As long as I turn it off, it will run fine upon restart, even if I do it right away.

Any ideas?

This post was edited by jjw2112 on Sat, May 31, 14 at 21:15