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Need 21BB Engine Help

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LarryA

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Things have gone from bad to worse. My engine is practically new and was running rather well except that it would eventually stall and not want to restart. Now nothing I do will make it keep running. As far as I know it was not run for any amount of time at a real high temperature. I had checked the temp quite often because I bought a new infered gauge. It seems like a carb problem but I just don't know anymore. If I reset the neddles to the factory settings it will not start at all. Fuel spits out the pipe pretty much. If I lean the bottom end about a turn or so I can get it started but only at about 1/4 throttle. It seems to make no difference where I set either needle it will not go to a slow idle and stay running. I cannot find anything loose to cause an air leak. I have tried another manufacture carb and that was about the same or worse. I have never had this kind of problem before. This engine ran good during the breakin and for about the first three or four times I ran the truck then went sour. I have been using an OS #8 plug and tried a McCoy #9 with no difference. I run with O'Donnell 20% fuel. Could it be the fuel, it was just purchased and opened about a week ago (after the problem actually started). I'd appreciate any help, I really can't afford an engine and that approach would park the truck for a long time to come. There has to be some of you out there that haven't switched to Ofna and Picco engines.
Thanks, Larry
 
Have you tried a MC Coy 59 plug? If not its a hot plug that might help you get running.
 
Try the pinch test? Start it and pinch the fuel line, it should take about 5 seconds for it to shut off. It is normaly hard to start when it is hot. I have to let mine cool down to about 160 before she"ll start again. How much smoke is coming out of the Pipe? Are you still on the first Gallon of Gas? Your back east so it is a lot more Humid than out here, You may have to lean her out just a bit more. Also, right after she stalls, check for air in the Fuel line. That was the big problem with My Savage. Had to get rid of the Primer button!
 
I can't understand it. I have plenty of fuel when it is running but the only way it will idle is with about 1/4 throttle. I have tried goin gback to the factory settings and starting over again (in which case I have to lean a bit or it will not start at all). I get it running that it has good top end and good take-off for an idle and no sooner do I reach this point and it just shuts off. It is not running too lean because there is plenty of smoke and I would have to say it isn't way rich or it would not run like it does (for the little it runs). I have check the temperature and I'm running at about 240-265 degrees, depending on how hard it was runnning before the check. Also, it NEVER runs the same two days in a row. I mean not even close. I did notice that the midrange needle seems to be real loose as far as resistance to movement (it turns really easy), escpecially if you try to put the bottom end back in to touch and reset the factory turns out. I'm barely touching the seat and the midrange needle starts turning. I beleive the whole proble is the carberator. The engine runs good while it is running but that is seldom lately. I have not done the pick test though. I have a hard enough time keeping it going long enough to even think I might be close to the proper carb settings. I wish my 21 OS carb would fit but the base is too large for the 21BB's intake opening. I haven't yet given up but I'm close to that and going for a Hyper 8 port. Big problen there is it going to be a while until I can afford and engine. I'm geberally running an OS #8 plug and O'Donnel fuel in 20%. Yesterday I tried some Wildcat fuel and the results were about the same. I have a little over a gallon of fuel through the engine and it has run on several occasions and stayed running for a tank before shutting off. I never had an engine act like this before.
 
Well, I had a similar issue but yours is worse. Here is what I did. First I did the Mod on the Primer button. It allows air into the gas tank. I was seeing air in the fuel line so I got rid of it, and it worked. Aslo, I had to richen up the Mid adjustment just a little, then locked it down with lock-tight. It is loose on mine too. Let her warm up with a full tank of gas in her. once warm, let it Idle. If you notice it Idles at various speeds, it may be the carburator.
You will notice the RPM fluxuating. You can remove the carburator,m clean the seals and then make sure you put her in and tighten her down good. Stick with the Same Fuel too. It took Mine a good Gallon and a half before she ran consistent. I just left her Fat (rich) and let her run "stupid" until I had a gallon of gas through her. I did have to go back to factory setting a few times too. Let us know..........
 
Originally posted by Markanthony
Well, I had a similar issue but yours is worse. Here is what I did. First I did the Mod on the Primer button. It allows air into the gas tank. I was seeing air in the fuel line so I got rid of it, and it worked...........
Click to expand...

How do you get rid of the primer button?, what do you use to cancel it?

I have the same problem.

Originally posted by LarryA
I can't understand it. I have plenty of fuel when it is running but the only way it will idle is with about 1/4 throttle. I have tried goin gback to the factory settings and starting over again (in which case I have to lean a bit or it will not start at all). I get it running that it has good top end and good take-off for an idle and no sooner do I reach this point and it just shuts off. It is not running too lean because there is plenty of smoke and I would have to say it isn't way rich or it would not run like it does (for the little it runs). I have check the temperature and I'm running at about 240-265 degrees, depending on how hard it was runnning before the check. Also, it NEVER runs the same two days in a row. I mean not even close. I did notice that the midrange needle seems to be real loose as far as resistance to movement (it turns really easy), escpecially if you try to put the bottom end back in to touch and reset the factory turns out. I'm barely touching the seat and the midrange needle starts turning. I beleive the whole proble is the carberator. The engine runs good while it is running but that is seldom lately. I have not done the pick test though. I have a hard enough time keeping it going long enough to even think I might be close to the proper carb settings. I wish my 21 OS carb would fit but the base is too large for the 21BB's intake opening. I haven't yet given up but I'm close to that and going for a Hyper 8 port. Big problen there is it going to be a while until I can afford and engine. I'm geberally running an OS #8 plug and O'Donnel fuel in 20%. Yesterday I tried some Wildcat fuel and the results were about the same. I have a little over a gallon of fuel through the engine and it has run on several occasions and stayed running for a tank before shutting off. I never had an engine act like this before.
Click to expand...

I was having the same problem, I take of the carb and reset it, then put a little heavy duty grease in the base to avoid an air leak.

Under the low speed boot I put some more grease.

Mount the carb, start the truck, lean the HSN a little and works like a charm.

I'm thinking to get rid of the primer button, but the problem is over already, maybe later....
 
all I did was remove the cap (pull on it), grab the primer shaft and pull it up as far as it will go. use the spring to seat the O-ring down as far as possible. (you'l see what I mean when you pull the cap off), maybe use a small screwdriver to push down on the O-ring. just make sure it is seated down as frar as it will go and evenly. then I used the two-part epoxy to seal around the primer shaft. After it sat overnight, I cut the shaft and off I went. I think Associated makes an in-line one way primer bulb for the same use. It is on the new Monster GT but not sure if it is available seperate from the truck. I have not seen any in my LHS.
Also, If your running a colder plug and it is not that hot outdoors, it is harder to start and harder to keep started at lower temps. Learned this when I went form Phoenix to Albuqueque and started it out there. These things are way tempermental to outside temp and Humidity.
 
I'm bit the bullet here and the worst result will be a trashed fuel tank. I eliminated the primer in the fuel tank. Not like described above but actually eliminated the entire primer plunger. I'd never know if I didn't try. This is what I did:
1. Pulled the primer button off the plunger with a pliers.
2. Cut the plunger as close to the tank as I could and not disturb the white tank plastic lip.
3. Put a piece of plastic under the tank lid to hold it open while I worked.
4. Went inside the tank with a long needle nose pliers and carefully removed the internal baffles preventing access to the primer plunger.
4. Use a long thin screw driver and and tool that looks like a bent awl. With these I pried the primer pluger from it's seat and bent it to the opposite end of the tank.
5. Used an allen head driver of appropriate size and pushed the plunger down from the top and into the tank.
6. Used needlenose and a utility knife (to stab small pieces) and removed all material inside the tank.
7. Use an Associated flat head aluminum machine screw and put a shock washer over the screw then a pice of fuel line the same as the deth of the tank primer lip. I then screwed the screw/washer/tubing assembly into the top of the primer hole. With the fuel tubing expanding and the washer at the top this should seal the tank without the need for any kind of expoxy (whick I thought may not hold to the plastic if any fuel residue is present).
7. Flushed out the tank and re-installed it on the truck and added a screened inline fuel filter.

Now I should only need to put a finger over the pipe to pressurize the tank. Fuel flow is unitterupted between the tank and carb. I reset the carb to factory settings to start over again and went back to the O.S. #8 glow plug and will stick with the O'Donnell 20% fuel.
Now I only wish for half decent weather to try it out, it has been doing nothing but rain here. Only about 3 days without rain for nearly two weeks or so. I'll let you know if it works or if I just found something else that doesn't work.
 
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Ok, I may be gettting closer to the cause of my problem. Today the engine started and ran fine while on a stand. The idle is still rather high but it kept running. Now I found that if I put the brake on (manually by just lightly applying backward force to the brake linkage wire or with the radio) the engine stalls instantly. By working the wire by hand I am eliminating the cause as the throttle body closing off the air flow. I have checked the throttle slide with the engine shut down and it does NOT close off. There appears to be plenty of opening for an idle speed. Could the problem be in my clutch? If I remeber correctly, I replaced the clutch with the Hot Bodies clutch but had to reuse the HPI springs (I could not get the Hot Body springs over the nut and into the slot). I'd really like to get this engine going. At first after breakin the truck was running rather well. I think I could do ok here if I could get it to idle without running away and without the brake on. I have it rather rich now so it seems to want more throttle to stay idling. Can't tell if the primer removal helped but it didn't hurt anything.
Any ideas?
 
It's finally fixed! I wish now I hadn't removed the primer but that's no big deal. Anyway. 98% of the problem turned out to be the Hot Bodies "Upgrade" clutch. I removed the clutch bell and the clutch shoe pieces came falling out. It literally ate the one up. Lighter spring or not, it should not have destroyed the shoe like that. I could see where it would engage at a slower rpm though. Now all I will need to do is to quite often check my fuel filter and clean the screen out. Tiny plastic chips from removing the primer. Otherwise it is running pretty good and only needs minor adjustment yet. Thanks to those who supplied any ideas.:breakdown
 
Yeah my hotbodies heavy duty clutch went out as well, and that was installed on a OFNA Hyper 8 port.
 
I only had the clutch on a very short time. From what I've seen here, I'd have to say that the hot Bodies clutches are junk. Heck, I still have the original clutch on my Super Athlete buggy and that is at least five years old. I think I'll just see how the factory shoes hold up. Maybe it will be worth it to just stay with the factory instead of chaning flywheel and whole setup to go with a three shoe (what I had figured on doing eventually).
 
Follow up: The Savage beast has run great the last two times out! It even restarted easily after a lid job that caused a flameout. I got carried away and temptation got the best of me. Against better judgment, I just had to try a little mud bogging in this somewhat drying out huge puddle. Had a ball but the truck looked really bad when I got it home. Took a LONG time to clean that mess up. Too bad you can't really just use the hose and give it an R/C car wash.:w00t:
 
Did it look anything like this when you were done?
50DSC00721.jpg


If not, you didn't do it right...
:D
 
Not quite but not far from it, except for being a really black ugly and a bit smelly mud :thumbup: All is well, the truck is realatively clean and happy again.
 

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