Phazer help

I have a 485 Phazer with a fresh rebuild, but it don't run right. It will run good then act like it is flooding out in the pulley side cylinder. I have gone through the carb mulitiple times and can't find anything wrong. Have checked timing, coil, changed plugs, and checked crank seals. I can't find anyting. Has anyone else had a similar problem or have any other ideas?

Thank You
Jake Crain
 
Jan 19, 2008
298
35
28
Wrangell, AK
I have built countless phazers.. and one of the biggest mistakes that people make during assembly is in the choke adjustment. If one of the cables is too tight, or the choke plunger is not seating fully, it will act exactly as described. It will run great when first started and cold, and as it warms up, will drop a cylinder.

You must make sure that the choke plunger moves freely in its port in the carb, and that there is no debri in the bottom of the port that may not allow the plunger to seat fully. If it does not seat, it WILL leak fuel, and richen the mixture. I adjust each cable so that when the choke lever is in the "off" position, you have about .030-.060" play in the outer cable housing when you pull the slack out of the adjustment barrel.

You must also double check the cables themselves. Not uncommon for one to be sticky enough so that the plunger spring is not strong enough to pull on the cable to seat the plungers.
 
Aug 3, 2008
559
31
28
North Idaho
OK, First question I have is did you put a new center seal in the crankshaft? New bearings? What did you use to seal the two case halves together? Yamabond? Not saying you did anything wrong just getting the bases down first because there isn't any sense telling you its in the carbs if the seals in the case are in backwards....if you know what I mean. I'll check back later on :)
 
Aug 3, 2008
559
31
28
North Idaho
I have built countless phazers.. and one of the biggest mistakes that people make during assembly is in the choke adjustment. If one of the cables is too tight, or the choke plunger is not seating fully, it will act exactly as described. It will run great when first started and cold, and as it warms up, will drop a cylinder.

You must make sure that the choke plunger moves freely in its port in the carb, and that there is no debri in the bottom of the port that may not allow the plunger to seat fully. If it does not seat, it WILL leak fuel, and richen the mixture. I adjust each cable so that when the choke lever is in the "off" position, you have about .030-.060" play in the outer cable housing when you pull the slack out of the adjustment barrel.

You must also double check the cables themselves. Not uncommon for one to be sticky enough so that the plunger spring is not strong enough to pull on the cable to seat the plungers.

Agree 100%. Make sure the springs are there, and that they have good tension. I know I asked about the bottom end which is good, but this might be a good quick check.
 
Aug 3, 2008
559
31
28
North Idaho
ok then, that is a good thing. Tell us more about what it does exactly. You fire it up, it runs smooth for a while? Then starts flooding on the Mag side? Is is smoking when it does this? Or is it just simply missing on that cylinder. I would have to do a compression test first just to make sure something didn't go wrong upon install of the piston (broken ring)...lets go from there, tell us what you see/find. right now I am thinking carbs/choke but you describe it.
 
How do the plugs look? Is the one thats dropping the cylinder fouled? Is the plug wet? I'm not too familiar with phazers but ignition coils do go bad, and can be intermittant and affected by heat....
If the problem is with the choke you should see it on the plug.
 
Jan 19, 2008
298
35
28
Wrangell, AK
Pulse hose is on the MAG side. His problem is on the PTO side.

I still think that it is a sticky/leaking choke plunger. OR, could be a bad float needle/seat assy.

There IS a pilot jet in that carb, right?? Seen guys forget to re-install them.

I am going to assume as well that the main jet nozzle is clean and the air-bleed emulsion holes are clear?? I would think that a LOT of them would have to be plugged for it to run that rich.

Had a local Yami dealer call me up once, knowing that I had alot of experience with phazers. He was having a similar problem on a newer chassis phazer ('00), and was stumped. I looked over all of the same stuff he had already checked. Then I asked him about the compression. "Compression is fine". So I inquired about secondary compression, meaning integrity of the crankcase. He looked at me funny like the idea had never occured to him..... and then we tested it. NO positive OR negative pressure in the PTO side of the crankcase. Bingo! Started looking for leaks or a hole in the bottom of the case. That is when I noticed that the PTO crank seal had blown completely out of the case. It was hard to see behind the clutch and bulkhead, but if you looked just right, you could see it plain as day. Sometimes it is the simplist things that our eyes just don't notice.

Just tossing ideas out there.....
 
This is how it works. It will start up and act a little flooded, but after a minute of idling it clears up. Then it runs good for a couple of minutes at full throtle and then it dies down to 3000 rmp like you let go of the throtle. Pull the plug and it is wet fouled. Burn it off with a lighter and it will run good again for a little bit and do it again. I can switch plug wires for one plug to the other and it stays with to PTO side cylinder. I have swap the float, needle jet, pilot jet, and main jet from one carb to the other with the same results. I have checked the crank seals with carb clean while it is running and the RPM never flared. The compression is 125 in both cylinders. I have check the timing twice. My next step was to change the PTO side carb body thinking there might be a crack internally in the carb. I have not yet check the choke seating as it has been sugested. I have noticed that one choke plunger has a nipple on it and the other does not, but I have switched then from one carb to the other with no change. That is the extent of the problem and what i have tried.
 
Aug 3, 2008
559
31
28
North Idaho
This is how it works. It will start up and act a little flooded, but after a minute of idling it clears up. Then it runs good for a couple of minutes at full throtle and then it dies down to 3000 rmp like you let go of the throtle. Pull the plug and it is wet fouled. Burn it off with a lighter and it will run good again for a little bit and do it again. I can switch plug wires for one plug to the other and it stays with to PTO side cylinder. I have swap the float, needle jet, pilot jet, and main jet from one carb to the other with the same results. I have checked the crank seals with carb clean while it is running and the RPM never flared. The compression is 125 in both cylinders. I have check the timing twice. My next step was to change the PTO side carb body thinking there might be a crack internally in the carb. I have not yet check the choke seating as it has been sugested. I have noticed that one choke plunger has a nipple on it and the other does not, but I have switched then from one carb to the other with no change. That is the extent of the problem and what i have tried.
OK, I quoted this one so I can keep up. We are down to two things. I would first check those choke cables, to my knowledge the ends should both have small tips on them. If one doesn't that is not good. Also they must fully seat in bore they go in, check this by comparing them side by side with each other, they should be the same length. To adjust, pull the boot up from around the cable and adjust the nut as desired. The only other thing I am thinking is if the pto cylinder isn't getting enough spark from a weak coil...? Not sure how you timed it when it wasn't running smooth? Is it or is it not hitting on that PTO cylinder. When its running pull the spark plug boot off each cylinder one at a time and see if it will still run, not change in rpm. I have seen plug caps go bad too, they have a resistor built in them so check there also. Hope its all helping.
 

shortman

Member
Lifetime Membership
Nov 28, 2007
183
8
18
newport nebraska
Carbs

Just checking are the black plugs inside the carb in the rite holes around the main jet? With carbs upside down, air box side away from you, the middle and right side holes should have black rubber plugs in them. The left one is left open. Had that happen to me once after cleaning carb, ran kinda like your describing, was missing the one on the pilot jet(right side)
 
Jan 19, 2008
298
35
28
Wrangell, AK
Mikuni made two types of choke plungers. One with a nipple, and one without. Yamaha used the nippled plungers. It is possible that the one without the nipple had been replaced previously. As long as the spring is pushing the plunger all the way to the bottom of the plunger well, they should seal the same. I have never seen a nipple broken off, but you might double check and make sure that one is not lodged in the bottom of the well. THAT could definately keep a plunger from seating.


I've got extra carbs, if you are interested in trying out another set. Parts may be stripped off of them, but it might be worth it to try out another set of castings. Buy me lunch, pay for shipping and they are yours...
 
I have changed the spark plug caps already. I also said that I can change spark plua wires from one plug to the other (because it is a waste spark system both plugs fire at the same time right) and it still stays in same cylinder. I will put and induction spark tester on the plug wires and when it does it the PTO cylinder always reads nothing and I can take the plug wire off that side and nothing changes. But that all can be caused by just a fouled plug.
With carbs when I got the sled it was all in peices (that is why I rebuilt the whole motor) and the carb guts where all busted and laying in a box. So I had buddy with a burned down Phazer and got the carbs off it. I put them on and it run like crap. So I took them a part and found it had no pilot jets in it (don't know how my buddies sled was running with them that way) and the little plugs where laying in the bowl. So I got the pilot jets out of the old set that come with mine and the plugs I had to RTV silicone in because they wouldn't stay. After that is when it started running the way that is does. So I don't know if they plugs in the carbs are leaking or not.
 
Premium Features