Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Model number 917.257561 18 HP Twin Cylinder We seem to have to crank and crank. We changed the spark plugs and installed a new 300+ CCA Battery. We are unsure if we should choke it until it fires or not choke it and see what happens. We have it at WOT and choke it. Once it is going it seems to run fine. Should we try an "add to gas" engine cleaner (Gumout Seafoam, etc.)? On a side note: We are looking for ways to add weight to the rear to balance out a front snowblower. THANKS

Sounds like your primer or choke/enriching circuit isn't working correctly. Try cranking the engine and spraying some gasoline directly into the carb and see if the engine fires up. If it does, and runs well, try reducing the throttle to see if your engine will run at medium speed and also if it will idle. Let us know how it goes. I suspect that if you have a primer (which I doubt), the line from your primer is either off of the carb or primer or leaking air thus impeding the fuel flow when priming. If you don't have a primer, check you choke linkage to make sure it's working correctly.

I HAD been starting well and running fine until today. I replaced the oil (Mobil 1 synthetic 5W30) and two new spark plugs. Today it was having a hard time starting again. In looking at the choke cable, I noticed it had a section that the covering had come off and the inside cable was exposed. I am planning on getting a new throttle cable. I am hoping to buy a universal and then cut it to the correct length. While I am there I will replace the fuel filter. Model number 917.257561

Does your rider have a low/no pressure oil switch on it? If so its possible that Mobil 5w30 is too thin to operate switch when cranking.Easy way to check is to remove wire from switch
when starting....if it starts right up it means you do not have enough oil pressure on cranking. Also a defective check valve in a oil filter will cause excessive cranking on startup too ( engines with low oil
pressure switch)

If you already have wheel weights and need more , have tires filled with 50/50 antifreeze .

It started great for over a week with the new oil in it. I do not know about no/low pressure switches. If that was the issue, would it not have been an issue from the first time I tried to start it after the oil change? I have little experience with engines but I read the manuals and ask questions on sites like this and then attack the problem. I will replace the choke cable and the fuel filter and then go from there. We bought the tractor with 42" snow blower with a homemade hard cab for $500 so if I need to put a few buck in it that is not an issue. In terms of weights: I have wheel weights and then I mounted a milk crate to the rear with threaded rod and loaded it with four 60# tubes of sand. I have had no real traction issues since adding the weight.

Well the choke cable has actually fine. Just the outer casing was worn. Now I am worried that I did damage by switching to synthetic oil. I was hoping to get better cold starts (we live in MN), but I am now reading about synthetics damaging seals in older engines. I checked the oil level and it seemed low. I see no spots on the ground, so the engine must be using oil. Should I switch back to regular (mineral) motor oil? I pulled the old plugs and they did not seem too fouled up. I am worried that with the new synthetic and using Seafoam in the gas I might be loosening up the gunk that is holding the engine together.

ramper wrote:

The only known problem to me with synthetic on older engines is the oil will burn more as blow by getting past the rings but can also leak through seals. I can't imagine you ran it that long to get a low reading when you checked the oil. You may not have initially put in enough oil. I would keep a non synthetic in it. If your rider isn't sitting level it wont be able to start due to the low oil safety switch. Awhile ago I was using a pressure washer on my driveway which is sloped and couldn't start it due to the same switch scenario. I just turned it around 180 deg and that ended my trouble. I did check to make sure there was enough oil while it was on a level surface.

So even though the synthetic has only been in the tractor for less than two weeks you would recommend that I change the oil again and switch back to a traditional oil?

I would say so but lets wait for more opinions on this. Did you add more oil to see if it would start due to the low oil safety switch issue? Also is your rider on level ground? Do you know for a fact gas is coming to the carb? Was your plug wet when you took it out after trying to start? let us know.

I did add oil and it did start eventually. The tractor was on level ground. The synthetic "seemed" to make the tractor start better on cold mornings.