99 Phazer Carb Question.

W

Washington

New member
Joined
Feb 1, 2021
Messages
5
Location
Central Washingtion
Hey
I am having a hard time getting a 99 Phazer to run right. I have had the carbs off twice, already. Everything is clean. I have a question about the black plugs in the float bowl. It has one plug unlike the earlier model Phazers which had two. That's the way it came. The online Yamaha illustrated parts list shows one plug in the center hole. Is this correct? It sounds like there was some problems with the documentation for the pre 1998 Phazers and it has been talked about in a couple of other places online. I should have paid more attention when I took it apart. The center hole it plugs in at the bottom of passage which is drilled so it vents into the float chamber making the plug seemingly ineffective. The plug is in remarkably good condition for it's age.

It is hard to start, barely runs (very rich, lots of smoke) and I am getting kinda frustrated. If you know for sure where the plug goes let me know.

If anyone has any other ideas on things to check I would like to hear them. I am running out of ideas. This may be a little too detailed of a problem to address in a forum.

Thanks for any help.
John
 
Yes, that is where it goes - this is the shorty right? the mountain lite still had the old engine and plugged 2 holes.

I suspect that your starters are not sealing or are misadjusted. Pull them out and possibly replace the plungers.

Also check the entire pilot circuit as i have seen these plugged.

Oil pumps tend to go full open when they fail, so this causes more smoke at idle but they usually run okay.
 
It is a trail sled. I was kind of wondering about the starter plugs. I put enough play in them to be sure they were fully seated but it was impossible to start. They physically look pretty good. No scoring or anything. I put an "All Balls" rebuild kit on it and I am thinking that one of the floats was hanging up on the new valve. They were a little different than the originals. I think I will go back to the old ones, they worked last year and still look ok. I have it jetted for altitude and didn't change that.

Why is the pilot circuit particularly problematic? The air and metering jets are clean, is there another place where evil can hide? As I recall the passage had a dogleg in it. I will take another look tomorrow.

Thanks for your help. I have a couple of things to look at.
 
You can also check the calibration of the 2 carbs. When throttle os complete open the butterfly’s should be the same hight. If you adjust those make sure you lift the back end when you start it cause it could rev a-lot more.
 
opposite on the oil cable - the pump has a ramp in it that increases oil ratio as it progresses through travel. More free play changes the ramp up to later in the throttle pull.
 
I have another carb question. I took the new float bowl valves/seat out and re-installed the old valves/seat. I was concerned that the valves from the kit were not sealing. I noticed can't blow any air past the valves even when the floats are down and valves should be fully open. The valve is still being held shut by the spring plunger on top of the valve. Is it normal that I just can't get enough air pressure from my lungs to open it? Float heights are correctly adjusted. It seems to me I have tried this on other carbs was able to get air past the valve. Any thoughts?
 
Just a couple of more comments. The float height is given as from 9.5 to 13.5mm. It was set at on the very high end at 13mm. When the float is fully down the tang was still on the spring loaded pin on the top of the valve. The valves would open at just about 2 psi on compresses air which is far too pressure to get with your lungs. I reset the float heights to 10 mm plus a little. Still within spec. Now it opens when the floats are dropped. The tang barely comes off the pin. The question is will it still seal when the floats are fully up and valve should be closed.
 
You must log in or register to reply here.


Back
Top