Bought this Sears tractor from the original owner about a month or so ago and had it running pretty good for a few days and then the fuel pump stopped working. Rebuilt the carb and put a new fuel pump in it and a new fuel line back to the tank and got it running again. Trouble is I cant seem to get the carb adjusted correctly to keep it running right. Anyone know where I could get a manual? Engine is an Onan BG-MS/2980A.
76 Sears SS-18 Almost running good
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here is link to a pdf engine manual.
http://www.cumminsonan.com/www/pdf/manuals/965-0251.pdf
this is a link to an site with a pdf owners manual for your tractor
http://www.searstractormanuals.com/
look on the left side.
the title is: http://www.searstractormanuals.com/manuals/91725960.pdf
http://www.cumminsonan.com/www/pdf/manuals/965-0251.pdf
this is a link to an site with a pdf owners manual for your tractor
http://www.searstractormanuals.com/
look on the left side.
the title is: http://www.searstractormanuals.com/manuals/91725960.pdf
Thanks! Thats exactly what I needed.
I bought this tractor from the original owner and its mechanically in great shape. It has the original spark plugs and points in it! When it first stated up and ran it was amazing how smooth it was. Cant wait to get it right again.
I bought this tractor from the original owner and its mechanically in great shape. It has the original spark plugs and points in it! When it first stated up and ran it was amazing how smooth it was. Cant wait to get it right again.
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15,197 Posts
Onan carbs are tricky. If they sit a long time some tiny holes in the carbs can get clogged causing surging, and if the o ring on the high speed needle is gone or dried it can gause gas to leak out... All in all, you have a much sought after tractor- I have an SS18 as well, they only made that model one year, and it has a great motor with oil filter too i might add. Enjoy it and keep that on up!
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1,017 Posts
pics of the oil leak would be a big help
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I've got one of these too, it's a fun, hard working little tractor! 
This one leaks a little oil too, and while I haven't investigated it too closely yet, it seems to be at the base where the oil drain tube leaves the engine. I need to pressure wash it all before I can tell for certain.
Mine is a 917.25961, essentially the same model. For no apparent logical reason, I love this thing, and keep it in better working order than either my old Ford truck, or my old Geo. :sidelaugh
Have fun with it, if you keep it tuned up it won't let you down :fing32:
This one leaks a little oil too, and while I haven't investigated it too closely yet, it seems to be at the base where the oil drain tube leaves the engine. I need to pressure wash it all before I can tell for certain.
Mine is a 917.25961, essentially the same model. For no apparent logical reason, I love this thing, and keep it in better working order than either my old Ford truck, or my old Geo. :sidelaugh
Have fun with it, if you keep it tuned up it won't let you down :fing32:
They are very cool tractors...something about a horizontally opposed engine I just love.
Last night I pulled the carb apart and reset the (fiber) float from 3/8" to 1/8" and the engine ran great untill the bowl filled up and fuel started pouring into the engine. So I started increasing the gap a little at a time to see where the best setting would be. In doing this I noticed the needle valve which has a rubber tip keeps sticking in the seat. No matter where I set the float the needle would stick and the bowl would run dry. This happened to the new needle and the old needle. This explains why I could never seem to get the float level correct. I finally set the thing to 1/4" and started it up.The engine ran great for about 20 seconds and then the fuel started pouring in again. I started tapping the carb and the motor started running good again. I think there is an issue with 1. the needle sticking in the seat and 2. the float sticking. Maybe this makes these carbs so difficult to get running right. Does anyone know where to get an all brass needle valve? I have also tried a new aftermarket brass float but it doesnt work at all. It seems to be too heavy.
I also looked around at the engine and took a few pictures. It has so much oil under it I cant see where it is coming from so I will give it a good washing and check later.
Once I get these little issues worked out I might just buy some paint and try to get it looking good again.
Last night I pulled the carb apart and reset the (fiber) float from 3/8" to 1/8" and the engine ran great untill the bowl filled up and fuel started pouring into the engine. So I started increasing the gap a little at a time to see where the best setting would be. In doing this I noticed the needle valve which has a rubber tip keeps sticking in the seat. No matter where I set the float the needle would stick and the bowl would run dry. This happened to the new needle and the old needle. This explains why I could never seem to get the float level correct. I finally set the thing to 1/4" and started it up.The engine ran great for about 20 seconds and then the fuel started pouring in again. I started tapping the carb and the motor started running good again. I think there is an issue with 1. the needle sticking in the seat and 2. the float sticking. Maybe this makes these carbs so difficult to get running right. Does anyone know where to get an all brass needle valve? I have also tried a new aftermarket brass float but it doesnt work at all. It seems to be too heavy.
I also looked around at the engine and took a few pictures. It has so much oil under it I cant see where it is coming from so I will give it a good washing and check later.
Once I get these little issues worked out I might just buy some paint and try to get it looking good again.
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2,576 Posts
The brass float needs a buoyancy spring to function correctly. Comes WITH a factory brass replacement float, not sure if you can buy it separate, maybe from boomer? As far as the needle sticking, usually you have to replace the needle AND seat as a set.
Joe
Joe
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125 Posts
Check to see if the float has gas in it. That would make it heavy. If you got it from 'Gary's Place' it could be the problem. Several of us here got floats from him and have been having problems with them.
I bought the carb kit with fuel pump as well as the brass float from Gary on Ebay.
I soaked the carb for two days, replaced needle valves, needle and seat, gaskets, fuel pump, fuel line basically everything.
When I started it after the rebuild the engine wouldn't run until I put the old float back in. Basically the problem was the float was too heavy to shut fuel off so it just poured gas down from the top. I told Gary about this and so far he has ignored me. I would not recommend buying his products.
The needle and seat were replaced together and they do stick. Then I tried the old needle and it also sticks. They both stick enough to hold the float in the closed position causing the bowl to run dry and the tractor to quit. I most likely replaced a perfectly good fuel pump thinking it was bad when it was the needle sticking.
The fiber float works for now so I won't make a change until needed. I do wish I could find a needle without the rubber tip.
I soaked the carb for two days, replaced needle valves, needle and seat, gaskets, fuel pump, fuel line basically everything.
When I started it after the rebuild the engine wouldn't run until I put the old float back in. Basically the problem was the float was too heavy to shut fuel off so it just poured gas down from the top. I told Gary about this and so far he has ignored me. I would not recommend buying his products.
The needle and seat were replaced together and they do stick. Then I tried the old needle and it also sticks. They both stick enough to hold the float in the closed position causing the bowl to run dry and the tractor to quit. I most likely replaced a perfectly good fuel pump thinking it was bad when it was the needle sticking.
The fiber float works for now so I won't make a change until needed. I do wish I could find a needle without the rubber tip.
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7,134 Posts
I am wondering if the ethanol in the fuel is causing the DD carbs problems after they sit in ethanol a while.
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7,134 Posts
Hugh SS16 usually tells people to add a little 30 weight oil to the fuel pump and he says they keep on working.
Did ya get it going again?
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I did get her running well. Started with new spark plugs (Autolite 216's). A new pair of solid core spark plug wires. A fresh tank of gas with fuel stabilizer in it. Seems the stabilizer helps but it might just be a coincidence.
I haven't put the air cleaner assembly back on it because I'm still fiddling with adjustments trying to get it to run consistently right. I've had to tap the side of the carb numerous times to get the float unstuck while it's running.
Need to get the choke knob and cable fixed and hopefully she'll be good to go. Wish I new where to get some used parts for one of these...
I haven't put the air cleaner assembly back on it because I'm still fiddling with adjustments trying to get it to run consistently right. I've had to tap the side of the carb numerous times to get the float unstuck while it's running.
Need to get the choke knob and cable fixed and hopefully she'll be good to go. Wish I new where to get some used parts for one of these...
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7,134 Posts
Sounds like ethanol and stabilizer need to be used.
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15,197 Posts
the fiber floats swell up in ethanol fuel- they stick on the sides of the carb when they raise up- that may be part of the issue. Before I found that out, I had 2 fiber floats that I would swap every two weeks to keep the tractor running. One would dry out, I would swap it for the swollen one, it would work till it swelled up
I will try to sand the floats a little and see if that helps.
I have a new problem now. When I start the tractor everything runs really good until the engine heats up. It sputters around and runs really rough and dies. Could I have a coil expanding and shorting itself out?
I have a new problem now. When I start the tractor everything runs really good until the engine heats up. It sputters around and runs really rough and dies. Could I have a coil expanding and shorting itself out?
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Actually soved the problem huh?
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