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Post by geh3333 on Apr 15, 2014 6:19:30 GMT -5
That sucks .
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Post by tvnacman on Apr 15, 2014 6:22:16 GMT -5
There is no external adjusting screw on the carb. Get out the small drill bit , I will see if I can post a pic of the spot . John |
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Post by tvnacman on Apr 15, 2014 8:35:09 GMT -5
There is no external adjusting screw on the carb. Get out the small drill bit , I will see if I can post a pic of the spot . John |
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Post by alleyoop on Apr 15, 2014 13:38:37 GMT -5
Here is a video drilling out the plug over the Fuel Ratio Mixture Screw:
Alleyoop
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Post by william42 on Apr 15, 2014 18:51:10 GMT -5
Well, I'm not sure that I want to go that route yet.
I bought a cheapo vacuum gauge and "T'd" it between the "Y" connector and the fuel pump. At idle I'm getting about 7 IN-Hg (which I assume is negetive pressure or vacuum). At no-load half throttle or so it drops to about 1 IN-Hg. That's still a vacuum but not much. I would assume that the flow of fuel would lesson too as I increase the rpm's but the opposite is true.
I "T'd" in a clear tube between the fuel pump and the carburetor and got very little, or no, fuel coming down the hose at idle (when the vacuum is greatest). When I increase the rpm's I got a steady flow of fuel coming down the tube. (I assume that the float bowl is full and the fuel coming out the clear tube is the excess from the fuel pump output. It's coming out the clear tube instead of returning to the tank.)
I am bewildered by this result. Why is there not LESS fuel when there's less vacuum?
I want to note too that there is a lot of air coming down the clear tube with the fuel especially when at high rpm's. I might not have a real good seal at the "T" but it's not leaking fuel so I don't know.
These tests were run under no load conditions. That is, the bike was on it's stand the whole time and the rear wheel was free to spin.
What do y'all think of these results?
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Post by alleyoop on Apr 15, 2014 19:23:18 GMT -5
I really hate to repeat myself, BUT put all the gauges away and please move the DAMN pump down to the floor so the gas from the tank flows to the pump.
And you will never get that thing to run right if you will not drill out the plug for the fuel ratio mixture screw or get an aftermarket carb. To pass Emissions tests for the EPA they set the carbs mixture really LEAN and are required to plug up the screw. But in our varying temps cause LEAN conditions right away and then people take it to their dealer and GUESS what the dealer puts in a carb with no plug on the fuel ratio screw and charges you for labor and a new carb and they keep yours drill the plug out and sell it to the next poor slob.
So please take some advice and you will be riding sooner rather than later.
Alleyoop
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Post by william42 on Apr 16, 2014 7:55:14 GMT -5
Wow! Really?!
I don't mean to get into a pissing match with you sir, but your solution doesn't fit the problem. As indicated in my above post there is more than enough fuel being delivered to the carburetor when the rpm's increase. There doesn't seem to be a need to move the fuel pump as it is doing it's job. And again, why would the manufacterer mount a fuel pump in a location where it won't work satisfactorily?
I might take your advice of differing the fuel mixture at some future point in time but certainly I will not do it during the break-in period.
If indeed the problem lies with the float bowl not being supplied with enough fuel (even though the figures indicate otherwise), enriching the fuel supply would then make the problem worse, would it not?
If you don't want to back up your claims with facts and figures and convince me that modifying my set-up will cure my problem, well, have a nice day sir!
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Post by alleyoop on Apr 16, 2014 14:34:02 GMT -5
I do not need gauges and figures to tell you what is wrong with your ride. I think I pretty well explained what your problems are and are pretty easy fixes. Does not take a genius to know mounting a fuel pump higher than the gas tank is a problem as well as having hoses with loops in them and a carb that you cannot adjust the Fuel Ratio Mixture, those are 101 problems right off the bat.
With that I bid you good luck, you have a very nice sharp looking scoot maybe some one else might chime in and try to help you.
Ride Safe
Alleyoop
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Post by geh3333 on Apr 16, 2014 15:58:38 GMT -5
Please listen to alley
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Post by bashan on Apr 17, 2014 0:17:37 GMT -5
I haven't read this whole thread but vacuum fuel pumps push and generally don't have a lot of suction. You've taken a couple of variables out of the equation that make your assumptions invalid. You have air in the line, those types of pumps are really inefficient and irregular when air is up against the diaphragm. Two, there is a shunt for when the pressure rises to a certain level it releases some of the pressure so the pump isn't damaged. I have installed many fuel pumps, ALL of the directions say mount the pump at the lowest point possible in the system so that fuel flows down into it. Here is a CF Moto 250 vacuum pump:
This configuration may be misleading you as the connection to the fuel tank is on top. The inlet to this system is on the bottom of the tank. The fuel in the tank tries to push the fuel through the delivery line to the level of fuel in the tank. It's the old "water seeks it's own level" concept. So the manufacturer is still mounting the pump at a low level, but it may appear it is not that low in the system.
You are assuming a one to one correlation between fuel delivery and vacuum level. It is the pulsations of the vac system that pump the fuel, NOT the vacuum level. It takes very little vacuum to actuate the diaphragm so the intensity isn't all that critical. They keep pumping as the vacuum drops with higher RPM because the pulsations are there and the vacuum does not drop below the critical point needed to work the diaphragm. At some high RPM there is a point where the pulsations become so rapid and the vacuum so weak the pump experiences a dramatic drop off in efficiency fuel delivery. The bowl empties and the bike starts to miss and surge. At that point riders may switch to an electric pump that uses an impeller that is not influenced by the variables of a vac system.
However, the vacuum only has to be strong enough to work the diaphragm. Measuring it means very little and there is a dubious correlation between rising vacuum and fuel delivery. John is right, listen to Alley, he has it nailed. Mount the pump low, make sure there are no vac leaks and button her up. |
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Post by tvnacman on Apr 17, 2014 3:48:20 GMT -5
Does this help any? This was before I had any problems at all. Well, except for starting it in the morning which is what the video is all about. in this video it sounds like a fuel problem , I still would have done the valves first . I have a pod filter on my engine I'm pulling about 20" at idle and will drop from 20' to about 7" when the butterfly is first opened if I hold it steady it will go back up to 20' . The carbs that are sealed , are sealed to meet EPA standards . Its too lean they run like poopie , if Alley is telling you its lean that is where my money is . I know when I used my vac gauge to adjust my carb the a/f mix screw effected my vacuume by almost 10" . With the above said , would look for a vac leak since you have the gauge you vac is too low . The intake manifolds are known for being cracked and creating a loss of vac and letting more air in to lean out the mix . With your gauge flex the carb in the rubber manifold and see if there any changes in vac take your time each different direction you flex it hold it and wait 30 seconds . Your fuel pump see if you can turn it over , relocate it mount it on the other ear turn it around . Put it on the ground if you need to to test it . Nobody here is looking to give you a hard time we have seen a lot of common problems yours is a little more tricky , in cyber space , it gets frustrating sometimes . John |
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Post by william42 on Apr 17, 2014 8:32:49 GMT -5
There is still the critical question that prevents me from making this modification. "Why would the manufacturer mount the fuel pump in this location if that location was going to cause problems?" And another thing I have to question is why did it work just fine for the first 102 miles and then fail and rapidy get worse? That suggests to me that something failed and that simply mounting the fuel pump in a different location is not going to fix a failed part or a vacuum leak.
I'll take all that you have said into consideration but I still want to get to the root of the problem and, in my opinion, we haven't found it yet. I'm going to "take her out" this morning and see what happens. If it dies on me again I'm going to see how much fuel is in the float bowl. It has a drain hose and screw so it will be easy and quick. That should tell me something.
Thanks again for all your replies...
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Post by axlegrease63 on Apr 17, 2014 20:25:05 GMT -5
I own 2 fly 150's and a Kymco 250 the gas tanks are on the floor and the fuel pumps are mounted 4 inches above the tanks and I have never had a fuel flow problem in three years I think the problem is in the carb or vaccum system just my thoughts you find the problem.
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Post by william42 on Apr 19, 2014 6:12:09 GMT -5
So, after a few short test runs, then a few longer ones at the dreaded 45 mph, I had no issues so I decided to chance it and take her to work. She ran like a champ.
And because I have no proof as to what the problem was, I can only speculate.
1. I replaced three vacuum lines so maybe one of them was the problem.
2. The overfill of the gas tank may have gotten gas into the Emmision System causing a problem until it dried out? (Grabbing at straws on that one I know)
3. Or maybe I didn't shut off the alarm system properly and it shut down the engine after 8 minutes (according to the owners manual). Or maybe it just doesn't work right?
I think I'll start a new thred on that one and see what y'all know of such things. I need to learn everything I can about my Scoot.
Thanks again everyone...
In hindsight, what I saw and gathered the engine seemed to be flooded, not starved for the lack of fuel. If I lost spark while driving wouldn't fuel continue to enter the cylinder, not burn, then flood it?
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Post by tvnacman on Apr 19, 2014 12:59:40 GMT -5
I'm glad to hear your running again trouble free . If you have an alarm and you want to use it for anti theft , get a better chain to lock it up . Most of the time we see people getting rid of the alarm due to problems , draining the battery , no start problems . Keep in mind you can roll your scooter on to a trailer by your self even if the alarm is sounding . If your running problem came from the alarm system , its telling you don't ride me .
John
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..BAD TO THE BONE..
