Loss of power and oil/fuel drip from exhaust

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bman333

New Member
Feb 26, 2010
8
0
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Santa Barbara, CA
Hi Guys!

Well, had my Dax 49cc running pretty nice for a few days and went to fire it up last night. It was going fine for about half a block then started losing power. Now when I fire her up it sputters and has barely any power at all (maybe 10%).

This morning I noticed a little oil/fuel puddle beneath my exhaust indicating that it had dripped out.

My thoughts are that perhaps my oil:fuel ratio might have had too much oil. The second indication that confirmed those thoughts is that there is a bit of oil around the spark plug on the engine. I was going for a 20:1 ratio for the first tank but think I might have put a little too much oil. Is it possible that I've clogged up the carb or clogged up the exhaust?

I was thinking of pulling the exhaust apart tonight and cleaning it out. I was also thinking that perhaps just draining the tank and mixing a new batch of oil/gas and being VERY precise w/ the ratios, then refilling and firing her up again.

Any other suggestions?

Thanks!
 
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Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
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up north now
The float may be sticking due to crud in the needle seat. Drop the float bowl, and remove the float and float needle to check it.

If you find any dirt, paint ect., run an inline filter. Good idea to run one anyhow.
 

bman333

New Member
Feb 26, 2010
8
0
0
Santa Barbara, CA
ok, so i got around to taking apart the carb and there was no crud/paint/dirt or anything in the needle seat. Everything looked clean. I have been running an inline filter btw =)

After putting it back together I tried starting up the bike about 10 or more times and it would start w/ very little power, I'd peddle with it for a bit and then the engine would sputter like it was beginning to take off and continue to randomly sputter as I go down the street but never fully engage. On around start 13 or so it finally took off and I went half a block and turned around. Heading back it lost power and went back to sputtering.

I did notice when taking off the fuel line that even though the fuel petcock was set to closed position, fuel was still coming out. Is it possible that this is flooding the engine?

Any other thoughts or suggestions?

Edit:
My plug is black and oily. Perhaps it is running too rich and I should try raising the clip up on the needle?
 
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GearNut

Active Member
Aug 19, 2009
5,104
11
38
San Diego, Kaliforgnia
It sounds to me like the float needle valve in the carburetor isn't sealing correctly or the float height setting is too high. The fact that your spark plug is black is a clear indicator that your air/ fuel ratio is too rich. A high float setting can cause that.
The fuel valve on the fuel tank should NOT dribble when turned to the off position. That alone suggests replacing the fuel valve is needed.

Resetting the clip on the slide needle is easy enough done, try it and carefully watch the results.
 

GearNut

Active Member
Aug 19, 2009
5,104
11
38
San Diego, Kaliforgnia
Another thought: Is the choke lever loose in the air cleaner back plate? Is it perhaps letting the choke plate fall down to the choke on position while the engine is running?
 

bman333

New Member
Feb 26, 2010
8
0
0
Santa Barbara, CA
The choke lever is pretty snug and is staying to the choke off position when running.

It must be the float height setting. Come to think of it, I think I remember looking at the float arm this morning and recall that it was angled in upwards....meaning that the float would be going all the way up and being way too high!

I am going to take it apart again tonight and bend it downwards if thats the case so the float will be lowered.

Thanks for the reply GearNut! :)
 

bman333

New Member
Feb 26, 2010
8
0
0
Santa Barbara, CA
So I took apart the carb and lowered the float level...not sure that was my issue in the first place though.

Before starting it up I pulled the spark plug and noticed the prong on the end was touching the inner part of the plug....meaning there was no gap. I bent the prong back out and fired her up no problem. Been running great since. YEAH!

I'm assuming this means a piston may have hit the bottom of the plug? I remember reading somewhere else on here where others had that issue and needed to take apart the engine and shave down the offending piece a bit. Granted, my motor is still in break in...maybe it happened when i took it off road the other day.

:) Still gonna move the clip up a notch on the slide needle b/c its running rich but other than that im lovin it!

thx for the help guys!
 

Allen_Wrench

Resident Mad Scientist
Feb 6, 2010
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Indianapolis
That's weird, about the electrode getting all touchy-feely on the plug. I'm assuming it didn't look like that when you put it in. I don't know what others would say, but I would definitely want to find out how that came to be. Even if you have to pull the head and/or jug and take a peek.
And I keep thinking back to how you said that fuel would drip out of the line, even with the petcock set to off/closed. I would still check it some more, but I think that petcock sounds bad. And it would cause trouble along the lines of what you describe.
 

Allen_Wrench

Resident Mad Scientist
Feb 6, 2010
2,784
26
36
Indianapolis
That's weird, about the electrode getting all touchy-feely on the plug. I'm assuming it didn't look like that when you put it in. I don't know what others would say, but I would definitely want to find out how that came to be. Even if you have to pull the head and/or jug and take a peek.
And I keep thinking back to how you said that fuel would drip out of the line, even with the petcock set to off/closed. I would still check it some more, but I think that petcock sounds bad. And it would cause trouble along the lines of what you describe.
*UPDATE: I got to thinking about what I wrote earlier about the plug thing. I wonder if, before, when the plug electrode got bent, it was screwed in tighter/deeper - just enough that the piston at TDC would touch it and when running would really nail it. Then, later, when you put it back in, you didn't torque it quite as much and now it's just a fraction-of-a-hair less deep, thus missing the piston. I hope that's what it is.
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
If you screw the plug in and it hits the piston, you have the wrong plug. Also, only partially screwing it in is a really bad idea.