rgc
Scoot Junior
Posts: 6
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Post by rgc on Nov 26, 2010 18:55:23 GMT -5
hi just a quick question on the Mikuni carburettor for the JOG50 engine,
my Delmer is the 2 stroke oil pump had failed some time back and the previous owner told me just to mix the oil in the tank 25-1,
now the carb has started playing up so i have ordered a new one
what I'm thinking is will this new carb succumb to the same fate as its predecessor by lack of proper oil being pumped into it through the correct port and not just mixed into the gas.
if its just unlucky that the carb has died and its OK to mix the oil ill leave the oil pump.
Richy
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Post by 90GTVert on Nov 26, 2010 19:34:26 GMT -5
It's fine to pre-mix your fuel and remove the oil injection system. Your carb failure is likely unrelated as long as you capped the port that the oil enters so nothing could get in there.
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Post by Fox on Nov 26, 2010 21:26:27 GMT -5
Have you considered cleaning the carb and installing a new in-line fuel filter between the carb and the tank? There's very little to go wrong on a 2T carb other than debris getting into it.
Maybe if you describe the symptoms the experts around here can help you fix it.
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rgc
Scoot Junior
Posts: 6
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Post by rgc on Nov 27, 2010 1:42:38 GMT -5
Thanks for the replies everyone  The new carb is on its way to me now so don't really want to try to fix the old one but i will defo add a fuel filter, The symptoms were it would start and run OK until the choke warmed up and once this happened it would splutter and stop like it was out of fuel, when it was running giving it any throttle would stall if held open. Richy |
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Post by tomcas on Nov 27, 2010 7:30:41 GMT -5
Your carb did not die because of the oil not being pumped into the injection port. It's just a hole on the side of the carb that exits in the carb throat and nothing else. If anything the premix adds a little more lubrication to the carb than injection would.
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Post by 90GTVert on Nov 27, 2010 9:04:54 GMT -5
Just don't toss your old carb. Sounds like something that could be fixed with cleaning and adjustment.
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Post by Fox on Nov 27, 2010 10:07:03 GMT -5
The symptoms were it would start and run OK until the choke warmed up and once this happened it would splutter and stop like it was out of fuel, when it was running giving it any throttle would stall if held open. That sounds like a bad auto enricher or a bad electrical connection to the enricher. The enricher works by allowing extra fuel into the combustion process for a minute or so while the engine is cold and then when the unit is on the pin extends outward and blocks off a port cutting off the extra fuel effectively leaning out the mixture. If the enricher goes bad or loses power then the extra fuel is always present so it'll run good cold for a little bit but after the engine warms up the mixture is too rich and the result is bogging and/or sputtering. When the new carb arrives, I would first try just switching the enrichers if they are identical and see if it works. Yeah, I would get a filter if you don't have one on there. |
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rgc
Scoot Junior
Posts: 6
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Post by rgc on Nov 27, 2010 12:33:49 GMT -5
The symptoms were it would start and run OK until the choke warmed up and once this happened it would splutter and stop like it was out of fuel, when it was running giving it any throttle would stall if held open. That sounds like a bad auto enricher or a bad electrical connection to the enricher. The enricher works by allowing extra fuel into the combustion process for a minute or so while the engine is cold and then when the unit is on the pin extends outward and blocks off a port cutting off the extra fuel effectively leaning out the mixture. If the enricher goes bad or loses power then the extra fuel is always present so it'll run good cold for a little bit but after the engine warms up the mixture is too rich and the result is bogging and/or sputtering. When the new carb arrives, I would first try just switching the enrichers if they are identical and see if it works. Yeah, I would get a filter if you don't have one on there. I've had the enricher out and tested it and it works as it should, i used this procedure shown here >> www.ajparts.net/how-to/test-procedure/ when it's fully extended thats when the problem starts, i can manually lift the plunger with the screws loose and it runs great. I'm sure 100% its working the way it should I'm guessing the carb has a blockage someplace but ill try swapping the Thermostatic Carburetor Plunger when it gets here |
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Post by tomcas on Nov 30, 2010 19:22:50 GMT -5
I've had the enricher out and tested it and it works as it should, i used this procedure shown here >> www.ajparts.net/how-to/test-procedure/ when it's fully extended thats when the problem starts, i can manually lift the plunger with the screws loose and it runs great. I'm sure 100% its working the way it should I'm guessing the carb has a blockage someplace but ill try swapping the Thermostatic Carburetor Plunger when it gets here If loosening the screws and lifting the plunger helps then it sounds like you are running too lean. In any case there's a more comprehensive test you can run with the choke attached to the carb. You can do this either with the carb on the bike or removed. You need to access the inlet face of the carb by removing the air cleaner hose. On this face you will find a small hole on the periphery of the inlet that leads to the choke. It's easy to identify which hole because you can see the outline of the communication passage leading to the choke plunger. Take a small hose and hold it over the hole and blow into the hose. Provided the bike has been off for 15 minutes or longer then air should flow freely into the hole. Energize the choke by disconnecting the choke electrical plug and applying 12 volts (AC or DC) to the choke terminals. You can also try doing this by just running the bike but it may not run well with the air cleaner removed. Within 5 minutes of the choke being energized you should not be able to blow air thru the hole. |
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Post by hunt78 on Jan 27, 2011 9:55:59 GMT -5
is it ok to leave the oil pump in if ur mixing it manually?
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Post by 90GTVert on Jan 27, 2011 10:43:06 GMT -5
No. If you pre-mix and don't disable the oil injection system you will have way too much oil. Even if you have no oil in the reservoir, it's best to remove or at least disable the pump. Why have extra drag on the engine (even if it's minimal) and risk the pump tearing up and seizing or something when you could remove it for free or the cost of a flywheel puller if you don't have one (you might need that for other things later if you plan to work on the scoot)? Besides that, it gets rid of clutter if you take everything out. 49ccscoot.proboards.com/index.cgi?board=yamajog&action=display&thread=564 |
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Post by hunt78 on Jan 27, 2011 11:36:26 GMT -5
cool i kinda thought thats what i had to do, thanks for the info.
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