Jeff in ND
Member
Few weeks ago I had this posting about the problems with the 1948 Z:
http://forums.yesterdaystractors.com/viewtopic.php?t=1146731
Total story here...
Tractor was sitting for about 2yrs when I initially tried to get it going the summer of 2012. My dad had passed earlier that year.
So far as I knew at the time it was running when parked. I had to clean off the points in the magneto to get spark. Then it would start and idle OK but would run rough, cut out and miss when the throttle was opened up or any need for some power was needed such as driving up a hill. I was trying to pull a hay rack around last summer to haul some cut trees and brush around and it was a delicate operation to keep the tractor from stalling.
When I first got it running I found out the kill switch was not working. I eventually found that the little tab under the cap was apparently missing so the stud for the kill switch wire was not connecting to the points. I found the tab fallen down inside and got it put where it belongs. My Mom recalled that my Dad had someone out to work on the mag a few years before, but I have no way of knowing now what was wrong with it and what they did.
So, this spring I installed some new plugs thinking that could be the issue. Didn't matter at all.
Then, as per the other posting, I noted that there was some hissing around the throttle shaft when the governor would open up the throttle. Thought that was messing up the mixture and causing the problem.
So, I had the carb apart and replaced the egg shaped throttle shaft and put a new rubber seal on it. I cleaned up the carb (inside was pretty clean actually) and resealed it. I had problems getting the tractor to start after re-install but that was due to the idle stop and idle mix screws being totally out of adjustment after I had things apart.
I have gotten the idle stop and mix screws sorted out now and the engine starts up and idles just fine again. But, still I have the problem I cannot rev the engine up much over a fast idle and as soon as I try to drive the tractor around up a slope or pull anything it cuts out. So, the vacuum leak around the throttle shaft must not have been the problem.
I even vented a bit of propane around the intake manifold looking for vacuum leaks but didn't find anything.
What else could be causing this? Does a mag have spark advance on it? Could the timing be messed up? It does not appear the mag has been off the tractor in decades but I am not sure. I tried to see if there was any arcing around the plug wires but didn't see anything.
I will mention I had the power valve in the carb unscrewed but didn't have the seat out. I blew air through there and put it back were it was. I tried adjusting it in and out a couple turns either way while test revving by forcing the throttle open via moving the governor arm but it didn't improve it any, actually tended to make it worse if anything.
I am about out of ideas. My next trip to the farm is over Labor Day and I am hoping to come up with something to try next by then...
Thanks.
http://forums.yesterdaystractors.com/viewtopic.php?t=1146731
Total story here...
Tractor was sitting for about 2yrs when I initially tried to get it going the summer of 2012. My dad had passed earlier that year.
So far as I knew at the time it was running when parked. I had to clean off the points in the magneto to get spark. Then it would start and idle OK but would run rough, cut out and miss when the throttle was opened up or any need for some power was needed such as driving up a hill. I was trying to pull a hay rack around last summer to haul some cut trees and brush around and it was a delicate operation to keep the tractor from stalling.
When I first got it running I found out the kill switch was not working. I eventually found that the little tab under the cap was apparently missing so the stud for the kill switch wire was not connecting to the points. I found the tab fallen down inside and got it put where it belongs. My Mom recalled that my Dad had someone out to work on the mag a few years before, but I have no way of knowing now what was wrong with it and what they did.
So, this spring I installed some new plugs thinking that could be the issue. Didn't matter at all.
Then, as per the other posting, I noted that there was some hissing around the throttle shaft when the governor would open up the throttle. Thought that was messing up the mixture and causing the problem.
So, I had the carb apart and replaced the egg shaped throttle shaft and put a new rubber seal on it. I cleaned up the carb (inside was pretty clean actually) and resealed it. I had problems getting the tractor to start after re-install but that was due to the idle stop and idle mix screws being totally out of adjustment after I had things apart.
I have gotten the idle stop and mix screws sorted out now and the engine starts up and idles just fine again. But, still I have the problem I cannot rev the engine up much over a fast idle and as soon as I try to drive the tractor around up a slope or pull anything it cuts out. So, the vacuum leak around the throttle shaft must not have been the problem.
I even vented a bit of propane around the intake manifold looking for vacuum leaks but didn't find anything.
What else could be causing this? Does a mag have spark advance on it? Could the timing be messed up? It does not appear the mag has been off the tractor in decades but I am not sure. I tried to see if there was any arcing around the plug wires but didn't see anything.
I will mention I had the power valve in the carb unscrewed but didn't have the seat out. I blew air through there and put it back were it was. I tried adjusting it in and out a couple turns either way while test revving by forcing the throttle open via moving the governor arm but it didn't improve it any, actually tended to make it worse if anything.
I am about out of ideas. My next trip to the farm is over Labor Day and I am hoping to come up with something to try next by then...
Thanks.