90's Phazer fouling plugs quickly

[DallanC]

This thread is a continuation of http://www.snowest.com/forum/showthread.php?t=46979

Ok so the basic run down. Sled was running great with just an off idle bog, rest of rpm range was good, sled ran strong through mid to high range. Took it home, pulled carbs and gave them a good cleaning. Put carbs back on and the off idle bog was gone, but the sled wont get much above 3500-4000 rpm and has weak power like a cylinder was misfiring. Also it was smoking much more than usual.

So I pulled the carbs again, tore down, cleaned and remounted them. While I was at it I replaced the spark plugs (old ones were black and oily). Fired it up and it ran great on the stand.... really great! It rev'd quickly up to 6000 several times so I shut it down for the night. Next day I noticed 1 carb bowl was leaking a little gas so I pulled the carbs again, fixed the leak and remounted them. I fired it up again and it started good but after half a minute it sounded like it was bogging again. I shut it down and pulled the plugs. The new PTO plug was fouled and was very oily and black, fan side was slightly oily and much cleaner.

I'm confident the carbs are working as they should but now I'm having what I assume is fouling plug problems and trying to figure out why. Before pulling the carbs the first time, the sled ran great except for the slight off idle bog. It makes me doubt something like loss of compression or other mechanical failure would suddenly be the cause.

What would cause the plug to foul so quickly? Too much oil? Too rich of fuel? I wonder if the choke on the PTO carb isnt seating correctly...? Would that foul a plug?

Really pisses me off the sled was running great with just the minor off idle bog, now its completely fooked up. I do have shop manuals and I've followed them exactly trying to figure this out.

Ideas or suggestions? Man I swear if I can just get it running halfway decent I'm going to sell it and get something newer like a RMK Edge or something else in that price range.

Any other forums out there more specialized with older yammy phazers?

Thanks in advance...


-DallanC

 

[DallanC]

One more thing, what is needed to convert this sled to run premix only? I've heard of alot of people doing it ... and recommending it. I wonder if that might solve some of my problems.


-DallanC

 

[retiredpop]

I wonder if the choke on the PTO carb isnt seating correctly...? Would that foul a plug?
It sure would. Check the adjustment per the shop manual. I wouldn't convert to premix. It won't help anything. You could try totally yamaha forums. http://www.totallyamaha.com/

 

[Scooter]

When you pulled the carbs apart did you lose one of the rubber plugs that covers the pilot jet? This is a common problem if one of these plugs are lost or overlooked during reasembly. If you look at Yamaha's parts fiche on thier web site, you will see the plug I am talking about.

 

[DallanC]

When you pulled the carbs apart did you lose one of the rubber plugs that covers the pilot jet? This is a common problem if one of these plugs are lost or overlooked during reasembly. If you look at Yamaha's parts fiche on thier web site, you will see the plug I am talking about.

AH HA! You might be on to something...!

Ok now lets discuss this. When I disassembled the carbs the first time, 1 carb had the pilot jet covered, the other carb had it plugged. I thought this was an error and uncovered both pilot jets ACCORDING TO THE MANUAL. (see attachment).

So are the jets supposed to covered or not? Is only 1 supposed to be covered or both? The manual shows them uncovered. Only 1 cylinder is flooding / fouling... so perhaps on that carb only I am supposed to plug the pilot jet? Why is there no mention of this in the manual???

/boggle


-DallanC

 

[Viper5]

I believe the plug (on both carbs) goes over the pilot jet, the picture in the manual is wrong ? My brother had this same problem I believe this fixed it.
Let me know.
Chris.

 

[Q-BALL]

that pic in the service manual is incorrect,was a discussion here several yrs. ago about it. i've got a '91 phazer out in a shed and both pilot jets along with the center wells are covered with the plugs,and this sled ran well the last time it was used several yrs. ago.

 

[Scooter]

Yamaha's manual does'nt do a good job of explaning that there are supposed to be 3 plugs there. I know they want to show that there is a pilot jet under one of the plugs, but they should have put in another step and picture such as " remove plug and you will see the pilot jet " or something to that effect.

Just to add, I have had to wittle a plug from a stick when one of these plugs was lost while on a ride. Out in the middle of no where a buddy changed jets and lost one so his machine ran like crap. Pulled carbs back apart and found the problem, so made one from a stick. Worked great the rest of the day.

 

[DallanC]

GENIOUS!
BRILLIANCE!


That was totally it! I pulled the carbs again and plugged off the pilot jets, reassembled and fired it up... ran perfectly! Luckily a blizzard had just blown through so the roads were snowy and took it for a spin down the street. Pulled 60mph before hitting the stop sign at the end of the block, spun it around and hit 60 again on the return trip.

Oh man I am a happy camper again! Thanks everyone for the advice and tips. All bogs are gone, sled is running in top shape... just in time for a new years eve spin tomorrow (have off from work... and with the latest storm blowing through, should be some fun snow to play in!).

I cant believe the manual seems to read incorrectly... ah well live and learn. Thank you everyone for the help and tips, you guys nailed it! Hopefully this is the last time I have to noodle with those carbs... although I must admit, I'm getting damn fast getting them off and back on ROFL

Again, many thanks to you all!


-DallanC

 

[Viper5]

Glad it worked for yah !

 

[Q-BALL]

 

[Scooter]

Glad to hear it was a simple fix.