O.S. FS 120 Surpass
#1

Thread Starter


Bax, this is a FS120 Surpass that leaks fuel from the regulator and pump. Has been setting for some time. I have run 15% thru it and runs strong until I remove the hot shot from the glow plug. Ran about 30cc's of fuel and seems to leak more. Towers has the carb assembly and pump, but if I can avoid the cost repairing this one. Any hope?
#2

My Feedback: (50)

I have had some luck in stopping the regulator from leaking by replacing the cover with this one https://www.towerhobbies.com/cgi-bin...p?I=LXLYD5&P=Z
It seems like the older one warps and doesn't seal as well as it needs to and the newer one has an improved design that seems stronger and does the job.
Your results may differ though.
It seems like the older one warps and doesn't seal as well as it needs to and the newer one has an improved design that seems stronger and does the job.
Your results may differ though.
#4

Thread Starter

Well, I replaced the regulater cover and that stoppoed the leak. I also replaced the pump, it to was leaking, now as soon as I remove the glow starter it quits. Been adjusting and get a good idle, then quits as soon as the glow starter is removed. I would like to get it running good, but about to give up. Does anyone have some suggestions?
#5

My Feedback: (50)

Well, I replaced the regulater cover and that stoppoed the leak. I also replaced the pump, it to was leaking, now as soon as I remove the glow starter it quits. Been adjusting and get a good idle, then quits as soon as the glow starter is removed. I would like to get it running good, but about to give up. Does anyone have some suggestions?
#8

Thread Starter

Yes, new os 4 stroke. Tried another to, no luck. It will idle rich for maybe a minute or less then sputters and wants to quit, Then I put the hot shot on and tweak a little more . When I get to lean with the low needle it will quit suddenly. Seems to have a very short window, even idling good it will still load up and quit. I tried the tee in the line from pump to carb with no luck. O-ring on the high needle valve looks good and the valves are really clean. Using cahusker's advice got it close, just can't find that sweet spot.
#9

My Feedback: (50)

One more thing to try. Start it and get it to full throttle, then open the high needle until it is really rich and let it run that way for a minute or two. Now close the high needle until you get max rpm's and just back off a click. If the engine will run steady at this high speed setting then start on the low speed needle and get it to where it will idle good and transition well..Sometime when these engines have been sitting for a long time the oil congeals in the needle areas and act like a blockage that just doesn't clear out at normal settings but does with the needle open wide.
If this doesn't work I would be willing to look at the engine for you if you were willing to send it to me, I'm 50+ years in the hobby and have repaired engines for many folks over the last 30+ years. Lane
If this doesn't work I would be willing to look at the engine for you if you were willing to send it to me, I'm 50+ years in the hobby and have repaired engines for many folks over the last 30+ years. Lane
The following users liked this post:
brickwoodward (01-23-2022)
The following users liked this post:
rcrichman (03-05-2020)
#12
Junior Member
Join Date: Dec 2021
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts

Hello hurst, I´ve got the very same engine as yours.
It ran Really well for 5 flights and than begun to leak on the Pressure regulator.
Did you have any luck on yours? Is it running in a reliable way?
thank you
Mauricio
It ran Really well for 5 flights and than begun to leak on the Pressure regulator.
Did you have any luck on yours? Is it running in a reliable way?
thank you
Mauricio