BeagleRock Posted November 5, 2018 Share Posted November 5, 2018 Hello all, MC 2150 speeds up when carb cleaner or starting fluid is sprayed on the throttle shaft. I've been told by a couple of people that it's no problem if fuel isn't leaking out of the shaft area. I've also been battling a vacuum leak since April right Gary! I found many leaks and fixed them "I think" whether by capping/plugging or eliminating some component's altogether ie; smog pump and tad solenoids etc. Well I firmly believe they're all gone which leaves 2 things, intake manifold or the remanufactured carb from National Carburetors. I'm leaning towards them since I get a whistling noise straight out of the throat of that thing and the Chinese choke pulloff was bad upon arrival. It's runs descent but there's a spot where you can just take your thumb and manually move the throttle about an 1/8-1/4" and it will die or run extremely rough. I can also duplicate the problem by turning the curb idle screw down until it too reaches the same throttle position. Ironically that's at the same place the choke positions itself upon a cold start and causes it to start excellent but quickly die, choke working well, I just thought it wasn't. Questions and comments welcome as I eagerly await a call from the carb place. Thanks so much guys! Link to comment Share on other sites More sharing options...
BeagleRock Posted November 5, 2018 Author Share Posted November 5, 2018 BTW nice new picture! Thought I was on the wrong forum Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 5, 2018 Share Posted November 5, 2018 If you can move the throttle shaft even 1/8", much less 1/4", then you have a problem, Houston. That's way too much wear and it'll cause erratic running since the throttle will close at a different point each time, and a vacuum leak. I've never seen that much movement on a carb. That's really extreme. Link to comment Share on other sites More sharing options...
BeagleRock Posted November 5, 2018 Author Share Posted November 5, 2018 If you can move the throttle shaft even 1/8", much less 1/4", then you have a problem, Houston. That's way too much wear and it'll cause erratic running since the throttle will close at a different point each time, and a vacuum leak. I've never seen that much movement on a carb. That's really extreme. I don't mean laterally, sorry 🙏 Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 5, 2018 Share Posted November 5, 2018 I don't mean laterally, sorry 🙏 Which way? Link to comment Share on other sites More sharing options...
BeagleRock Posted November 6, 2018 Author Share Posted November 6, 2018 Which way? Just moving it back towards the cab as the throttle cable would do. Basically just giving it a very small amount of gas if you will. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 6, 2018 Share Posted November 6, 2018 Just moving it back towards the cab as the throttle cable would do. Basically just giving it a very small amount of gas if you will. Oh, I completely misunderstood. So, to say it another way, there's a spot in the throttle movement where it runs really poorly. Is that correct? Link to comment Share on other sites More sharing options...
BeagleRock Posted November 6, 2018 Author Share Posted November 6, 2018 Oh, I completely misunderstood. So, to say it another way, there's a spot in the throttle movement where it runs really poorly. Is that correct? Yes, very early on throttle movement, I can spray starting fluid on the outside or where the throttle shaft enters the carburetor and it will speed up .I feel I've eliminated everything else Gary, I mean there's nothing else to plug. I've removed the brake booster hose, replaced transmission vacuum hose and hvac lines. I'm leaning towards the carburetor because I can duplicate the condition every time with or without the afore mentioned items in the loop.I'm very discouraged! Link to comment Share on other sites More sharing options...
BeagleRock Posted November 6, 2018 Author Share Posted November 6, 2018 Yes, very early on throttle movement, I can spray starting fluid on the outside or where the throttle shaft enters the carburetor and it will speed up .I feel I've eliminated everything else Gary, I mean there's nothing else to plug. I've removed the brake booster hose, replaced transmission vacuum hose and hvac lines. I'm leaning towards the carburetor because I can duplicate the condition every time with or without the afore mentioned items in the loop.I'm very discouraged! Oh and yes the accelerator pump is functioning correctly + it doesn't matter in this particular scenario imo .I could be wrong, it happens often Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 6, 2018 Share Posted November 6, 2018 Oh and yes the accelerator pump is functioning correctly + it doesn't matter in this particular scenario imo .I could be wrong, it happens often Well, you raised a question in my mind: Is the poor running while the engine is in transition between one RPM, say idle, and another RPM? Or does it continue to run poorly with the throttle cracked open that 1/8 - 1/4"? Just want to make sure I understand. Link to comment Share on other sites More sharing options...
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