riding mower

[cj]

My MTD riding mower with a 17.5 Briggs and Stratton has been having a hard time rolling over when I go to start it. When I turn the key the starter will not roll over at first, it seems to struggle at first but the it turns over. It's almost as if there is to much compression to over come. The last two times I mowed my lawn after about 5 minutes there is a noticeable loss of power and then the motor starts to sputter and now has quit. I am thinking that it could be sticking valves or perhaps crankcase ventilation. Any comments/input would be appreciated. Thanks, CJ

[Big Al]

Pull the spark plugs and see how it cranks.

[John Grabowski]

*No expert here, but have you checked the battery lately? Is it getting charged? Do you have a spark at the plugs?

[RBM]

Could be a timing issue

[cj]

I did and it cranks fine

cj

[cj]

Battery if good and a year old starter

cj

[willshak]

Dirty gas filter or blockage of gas line? If you already checked that, please tell us everything you did check so we don't have to guess.

[bob haller]

try putting jumper cables from a vehicle to the mowers battery.

if it still cranks poorly that will elminate a battery or charging issue....

charging voltage with mower running should be around 13.8 at the battery, any lower and the generator isnt charging properly

[David L. Martel]

CJ,

Overhead valves? Check and adjust your valves. They may be too loose.

Dave M.

[Denis G.]

+1 Here's a video for the OP:

[Stormin Mormon]

and now has quit. I am thinking that it could be sticking valves or perhaps crankcase ventilation. Any comments/input would be appreciated. Thanks, CJ

[hrhofmann]

When did you check the oil????

[gregz]

I got a brand new battery I'm having trouble starting mine. It could be connections or faulty battery. Last year mower just started slowing down. This year I started it, and with a bunch of smoke, settled down and ran fine. Can't figure, maybe gas flow.

I'll check the battery out with harbor freight tester.

Greg

[The Daring Dufas]

I would expect to see a voltage of at least 14 volts but not as high as

15 volts. The best way to check it is with an ammeter. Even cheap multimeters will handle 10 amps DC. I doubt a riding mower charging system is going to put out more than 10 amps DC. ^_^

TDD

[The Daring Dufas]

When I was servicing a lot of residential generators, I would have to adjust the valves on the engines after the things had been in for about a year or after a prolonged power outage from a storm where the gensets had been running for days. It wasn't all that difficult on the Generac generators that had the B&S Vanguard V-twin. The last one I installed had the Generac developed and manufactured big honkin' V-twin engine that seems to be bulletproof. ^_^

TDD

[Denis G.]

I replaced the head on my neighbors riding mower last summer after it swallowed the exhaust valve when the valve guide came loose (supposedly common problem for that vintage - mid to late 90s). It was a 14.5 BS OHV and I went through the exercise for adjusting the valve clearance. He was ready to junk it, but I said that I could fix it cheaply for him and I got the parts from Sears. Out of curiosity I split the case and examined the part on the exhaust cam that does the compression release at low RPM. My neighbor replaced the battery this year, but it's still going strong.

[The Daring Dufas]

If it's the B&S Vanguard, it's actually a pretty good engine if you keep it serviced, especially changing the oil. I thought it was funny that the Vanguard used the same oil filter as my old 2.2L Dodge K-car. ^_^

TDD

[Denis G.]

The one that I worked on was a 28N707- single OHV 14.5 hp.

[The Daring Dufas]

Well heck, it's a horizontal engine like the Vanguard in the older 8kw Generac residential generators because the generator was belt driven and sitting vertically next to the engine. The valves should be just as easy to adjust. I think I have a piece of shim stock somewhere I cut to make it simpler to set the valve clearance of which I don't remember the value. Must be in some of those dead brain cells I lost along the way. Now when I write horizontal, I'm referring to the plane the flywheel and piston are in, the shaft is vertical. ^_^

TDD

[trader4]

I wish I had done that test with a neighbor's riding mower. He had the same problem, starter would not turn it over, even with a new battery and connecting the battery directly to the starter with jumper cables to bypass the solenoid and everything else. It would engage and try to turn it, but just could not. I was convinced it had to be a bad starter. He bought a new one and same thing.

He finally had Sears come out to fix it and they told him it was the valve adjustment. Sounded bizarre to me, especially since he as a small lawn, the mower wasn't that old, maybe 5 -7 years and otherwise worked fine. But apparently they rely on some sort of compression release system to reduce the torque required. When the valves get out of adjustment, apparently that must affect the compression release system.

The fact that it spins with the plugs out suggests you have a similar problem.