My new Lawn Tractor

Mower trouble? Are 2-cycle engines the bane of your existence?
Fast_Ed
Posts: 550
Joined: Wed Oct 23, 2013 9:45 pm

My new Lawn Tractor

Post by Fast_Ed »

Lawnmower.
Lawnmower.
My neighbor decided to give me his non running Murray 4250008x lawn tractor a couple days ago. I havent taken a good pic of the whole thing, but I have quite a few of its individual parts.

It has a briggs 16.5 vertical shaft motor model 310707.

The guy did not claim to be very techivalry but was very proud to tell me that he had successfully replaced the carburetor. I believe him because the carb appears new (and for another reason I'll get to later). It ran for a while after the carb replacement, then made some popping and smoking and stopped running. He decided to give up on it and it lived in his shed for several years.

I rolled it across the street. Olivia did a decent job of steering it for me in the driveway. On first inspection, the guy must really have cared for the mower. The battery was disconnected and probably had been on a trickle charger at some point. It was in the tray backwards so must have been removed at some point after the 'last run'. The fuel system had been drained. Score!

And that's all I had time for the first day.
Last edited by Fast_Ed on Wed Jun 21, 2017 9:28 pm, edited 3 times in total.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: My new Lawn Tractor

Post by kevm14 »

That sounds fun. I love projects like that. Model # seems to indicate a 42" cut. Mine is also a 42" which is a good size to have.

https://www.briggsandstratton.com/na/en ... ted=310707

I didn't know Briggs made a 16.5 hp single cylinder engine. It is 501cc! OHV, too. So fancy. For oil, if it is a summer only machine, you could use a detergent SAE 30. Manual says you could also use a synthetic 10W-30. I have done some research and you could also use a good HDEO 15W-40 - I am partial to Delo 400, but there is Mobil and Shell as well. I switched to that in my lawn tractor and generator.

I guess you need to take stock of what you have on that engine. It may or may not have an oil filter or fuel pump. It will have some kind of fuel filter most likely. Once you get a battery hooked up or rig up jumper cables, I'd make sure it turns over and sounds right. Check the spark plug also. Then while cranking I'd probably mist a little starting fluid into the carb and see if it kicks/runs. If it does, you have spark - or enough spark to run probably. Determining if you need to focus on fuel or ignition is kind of where I am going with this. It could have problems with both for all you know. Make sure the choke isn't stuck on or something dumb like that. It's the outer-most throttle blade on the carb.
Fast_Ed
Posts: 550
Joined: Wed Oct 23, 2013 9:45 pm

Re: My new Lawn Tractor

Post by Fast_Ed »

So last night I checked the plug/air filter/oil/batt voltage. They were nearly new/also nearly new/clean and full/10.5 volts.

So I jumped it off the roadmaster.... more to come.
Fast_Ed
Posts: 550
Joined: Wed Oct 23, 2013 9:45 pm

Re: My new Lawn Tractor

Post by Fast_Ed »

It would crank over once the battery had charged some. I added some fuel and it ecen started for a bit. It was quite loud with a very noticeable exhaust leak. After less than a minute, it stumbled, backfired, and stalled. I let it sit to charge and was able to get it to start agan with a bunch of cranking. Then I ran out of time again.
Fast_Ed
Posts: 550
Joined: Wed Oct 23, 2013 9:45 pm

Re: My new Lawn Tractor

Post by Fast_Ed »

I took off the muffler to see what was going on there. The bolts were loose and the gasket was broken. Easy fix there obviously. It was about this time that I noticed the puddles under the motor. Probably oil. No obvious oil leaks on the upper part of the motor.. I couldn't find any on the pulley by feel either.. I guess that would have been the bottom main seal?? So I rolled it up onto car ramps to look under..

I never found the leak because fuel began dripping on my head when I stuck it under the mower. It was coming from the vent tube which connects to the input of the carb. Removing the casing/air cleaner revealed that the carb intake tube was half full of gasoline.
Carb and drain back valve
Carb and drain back valve
That made me suspect a float issue. But I had no time or gasket to pull the float bowl. Since I needed to stop the leaking, I emptied the tank by pulling the fuel line. I also wanted to drain the carb, which had an anti backfire solenoid on it where I would have expected a drain plug. The connector for the valve was dangling free. I wonder if the valve was never reconnected after the guy replaced the carb?? That's about where I left it.
Fast_Ed
Posts: 550
Joined: Wed Oct 23, 2013 9:45 pm

Re: My new Lawn Tractor

Post by Fast_Ed »

kevm14 wrote:That sounds fun. I love projects like that. Model # seems to indicate a 42" cut. Mine is also a 42" which is a good size to have.

https://www.briggsandstratton.com/na/en ... ted=310707

I didn't know Briggs made a 16.5 hp single cylinder engine. It is 501cc! OHV, too. So fancy.
Yeah, 42" cut will make quick work of my lawn, which will be nice.

My motorcycle is like 498cc, so the tractor beats it there. And with only one cylinder!
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: My new Lawn Tractor

Post by kevm14 »

I noticed the carb says Nikki on it. In my reading for addressing the carb issues on my own lawn tractor when I got it, I did stumble onto some stuff that said the Nikki carbs can be troublesome. Based on a quick search just now, replacing the carb was probably the right thing to do though usually I prefer to inspect, clean and rebuild.

My solenoid is not at the bottom of the carb bowl - I assume it is doing the same thing.
Fast_Ed
Posts: 550
Joined: Wed Oct 23, 2013 9:45 pm

Re: My new Lawn Tractor

Post by Fast_Ed »

Well, I did clean the float needle seat, which helped with the fuel leak issue. Got it started but it would pour out white smoke and stall. I checked the oil and there was significant overfill.

When I changed the oil it was super thin and smelled like gas. Clearly the float issue had caused fuel dilution. An oil change later and I was able to drive up and down the driveway. Sweet!
Fast_Ed
Posts: 550
Joined: Wed Oct 23, 2013 9:45 pm

Re: My new Lawn Tractor

Post by Fast_Ed »

I did a valve adjustment and installed a new battery. Starts like a charm now! I mowed the lawn with it until I ran out of fuel.

I need to work on my technique and sharpen the blades. I also need to flatten out some lawn holes.

But I could certainly get used to mowing this way!
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: My new Lawn Tractor

Post by kevm14 »

Please use hearing protection. It doesn't seem like much but the time involved makes it more detrimental than you may think.

I sharpen my blades on my bench grinder. If they are totally trashed I'd replace them. To remove them, I actually pull the deck. There are other ways. Use an impact and it will simplify the operation greatly since you won't have to block the blades with wood or anything.
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