Help with a Gravely L walk behind

[Lenny Vess]

I have a 1960 gravely 6.6 hp walk behind that has some issues that I need help with. I was mowing the other day and noticed that it started losing power and began smoking before it cut off. I had checked the oil level prior to firing it up and it was fine. I checked the oil pressure just before it shut off and it was reading "low". I let it cool down and then added some oil and it fired right back up. Within 10 minutes it started losing power again and shut off again. I have not tried to start it since. It was not knocking or making any unusual noises before it shut off. Any help on where to start looking would be greatly appreciated. I love this tractor and want to revive her. Thanks again for any help.
 

[joe csuti]

Goto link below & read some of the service manuals/info posted at site,may give you some hints as to cause of problem,there may have been lube issues with eng as an instruction manual is posted for a updated conversion lube system.

For the problem you have,possible causes-oil wrong wt(should be SAE 40)plugged/restricted oil filter,worn oil pump,excessive internal wear causeing loss/low oil pressure after eng gets hot due to expansion of parts.
gravely

 

[Bret4207]

Check the oil first, if it's low, refill. Check for oil leaks. On several of mine the rear frame for the sulky and oil line have come in contact and worn a hole in the oil line. The oil pump on these is very small and is a low pressure design. If you have a filter, and not all of them do, it could be clogged.

Next check the head fins for dirt/mud and make sure all the air direction baffles are there. I've bought a mess of Gravelys with missing baffles and they don't cool well at all without them. Make sure the fan belt is in good shape and tight enough, it takes a pretty thin wrench to get to the inside nut, but it can be done.

Check the timing. It's not at all unusual for the timing to be off a bit due to wear, vibration, worn points. That can lead to poor performance just as you describe.

Check for carbon build up on the piston/head/valves. That's a low compression engine and a little carbon can make things go wrong pretty quick.

Usually when it starts smoking and dies out, part of that is worn rings and the crankcase/oil fill vent being plugged with dirt. Easy to wash it out.

The Gravely is a fantastic design for the application, but it's an old tractor friend. It may come time for a rebuild if it's wear causing your trouble.
 

[Lenny Vess]

Thanks for the advice that I have received. At least I have a starting point to see if I can locate the problem. I probably will not get to it until after Christmas (I have to make Christmas presents) but I will post my results when I find out what it is. Thanks again for the help.
 

[Bret4207]

There is also a Yahoo Gravely board you can go to for help. I hate, Hate, HATE!!!! Yahoos system, but the info is good.
 

[Lenny Vess]

Just as a follow up, I had a couple hours the other day and decided to take a look at the gravely. I pulled the shroud off the tractor then removed the engine guard and discovered that there was an awful lot of thistle silk that seemed to be hugging the engine as well as the rest of the tractor. I removed the silk, scraped off all the exceevive dirt and grease, removed the plug and cleaned it, removed thw air filter and cleaned it out, and finally removed the oil filler cap and cleaned it. I put everything back together and prayed. It worked like a charm. The oil pressure read normal and I mowed for about an hour and it never cut off and kept the oil pressure. Thanks for the suggestions it seems sometimes we forget the obvious. Thanks again and Merry Christmas to all.
 

[Bret4207]

Glad it worked out for you! I learned the same thing you did the hard way back int he pre-internet days.