DC CDI  By  gy6girl (Read 2,918 times)

I had something similar when it warmed up it would lose power. Turned out I had cracks in the air hose from the filter to the carb. Changed it out and running fine now. If it is cracked and sucking extra air in, wrap some duct tape around it until the new part arrives.

Done all that...

Again...
The problem is not the carb, coil, spark plug, fuel enricher, CDI, valves, or air intake.

I guess I should explain in more detail...
Carb is not the problem, been changed out.
Coil, spark plug, enricher, CDI, air filter, are all brand new.
The valves have been adjusted.

Still loses power and runs rich, no matter how it's adjusted.

Also has an oil leak that I can't find. I think they are related in some way.

Sometimes it just takes a new set of eyes on the problem. It sure sounds like a air/fuel problem. If you have a friend that is willing to look at it and knows something about motors, the new eyes might see the problem.

I own three scooters.

As for the carb.. I have changed out the carbs with the other scooter carbs and it still did the same thing.
The other scooters run just fine.

I say it's running rich because of the gas millage it's getting. Aweful!

I tried a different CDI because when you go full speed, it goes just fine, then stalls out.
You have to slow down, and then it will fix itself. So I thought it might be overclocking the stock CDI.
It's not. Still does it with a racing CDI.

As for the oil.. If I knew where it was coming out I could fix it.
It's coming out while I am driving and it's getting all over the engine.
Then when I stop it all runs down and drips.
It's hard to know where the leak is when the entire engine is dripping.

I thought it was the little drain off part that catches oil from the cam shaft area, but I plugged that up completely, and it still leaks.

I know a little bit of this stuff.
I have fixed all three scooters by myself, but this problem has got me.

I like that idea on the vent hose. I will do that and I have an extra fuel filter right here.
But today was the first time I plugged it up. It hasn't been plugged up this whole time.
Most of the time it was connected to the stock air filter box.
But recently I bought a high performance air filter, so I had no where to go with it. I had it shoved down into the run-off tube.
I figured that was still what was leaking, that's why I plugged it.
I don't think that was it. It's still leaking some where.

As for it leaking on the valve cover, I don't think so.
For one I had it off adjusting the valves and it looked fine.
I know it looked fine because one of my other scooters was leaking there and I did have to replace it.
So it was actually one of the things I checked first.
As for the crank seal, you may be closer with that.

That's the only place I can think it might be.

As for the engine running...
Right now, you can start it cold without giving it any gas.
Just hit the starter and it will turn over instantly.
You will have to eventually give it a little gas to keep it going.
Rev it a little and let it warm up, it will idle just fine.

Out on the road, it runs pretty good. Has decent pick up and you can get going pretty fast. Not as fast as my other scooters, but you can get it up there.
But then once it starts getting hot...
Then it starts acting weird.

For example... Today I was going along at top speed, and then going up a pretty steep hill. I had the throttle wide open.
As I was going up, and bogging down, I could feel hesitance in the engine. Like some grumbles.
Then, it does it's thing.
It stalls out. All the sudden, no power.
The engine is still running, but no power.
So you have to let off the throttle and let it idle for a second or two, then you can give it some gas to get some speed up again.

It does this every time it's wide open. Whether it's going up hill getting bogged down, or going down hill at top speed.
It still stalls out.
And after that it seems like it's lost power all the way around.

Then let it set and cool off, it's back to starting up first try and working fine while not hot.
Go figure?

From your description of what happens it may be the Carb Bowl is not filling up fast enough. Try cracking the Gas Cap open a little just from the lock position crack it open still on but not in the locked position. It may be the tank gas tank is not venting and when that happens it will not let gas flow to the Petcock and it starves the carb. So as you back off it gets a chance to fill some of the carb bowl of fuel again.

The other thing is that since you put on a high performance filter it is not running rich it is running LEAN and getting to hot to the point of almost seizing on you. Whenever you put on a free flow Filter you normally have to put in a main jet 2 sizes bigger to match the amount of air coming in. That is why the other carbs from the other scooters act the same way. If this is a 150 get a 110 MAIN JET and stick it in there. If with a Free Flow Filter and you put on a Free Flow Exhaust then you will need a 112 or 115 main jet.
Alleyoop

So you have a Fuel Pump how are the lines from the pump to the carb running and where is the FUEL FILTER and is it on the right way. I have a Fuel pump on mine as well my tank holds almost 5 gallons it is up front my fuel pump is bolted on the bottom rail. The pump may work good at low rpms but not at high rpms. At high rpms there is a lot less vacuum created and it may not be pumping the gas up to the carb to keep it filled. You can try a Mikuni fuel pump they pump a lot of fuel more than enough.

www.aircraftspruce.com/catalog/eppages/mikunifuelpump1.php

If its a 150 and you did not change or modify the carb it has a 24mm carb and they come with a pilot jet #35 which is fine and a Main Jet anywhere from 103-105 and if you add a Free Flow Filter you have to upjet at least to a 108 or 110 or you will run the sucker LEAN at high rpms.
Alleyoop