Need help tuning Phazer

S

sleeper_dave

New member
Joined
Oct 26, 2009
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111
Age
45
Location
St Clair Shores, MI
I have an '85 (I think) Phazer 500 (480E). I bought it semi-running last year ($300), did the bare minimum to it, and beat the piss out of it for the winter until a bearing in the drive (primary, secondary, whatever the shaft with the brake on it is called) broke. I'm in the process of fixing that, and since i'm showing it some love I want to fix the fuel issue I had all last winter.

I got it to idle beautifully. Electric start works, she fires right up at the turn of the key and purrs like a kitten. But when you hit the gas, it wants to die (it will die) unless you play with the enrichment jet (starter jet, "choke"). If you pull the enrichment jet as you hit the gas, it'll run fine all day long (a little flat in places, but good enough for a $300 ski) until you come to a stop, then you better get off the enrichment jet or it'll stall.

This tells me it's lean anywhere but at idle. So I increased main jet sizes. Did it incrementally, but ended up way overjetting with only minimal improvement. Of course, before I increased jet sizes I went through the carbs and cleaned everything up, made sure the floats float, and of course raised the floats. I did put them back to normal when I was playing with the jets, I pretty much covered any combination of raised float / bigger jet that I could last winter.

So, this year I'm thinking maybe it's not a carb problem, it's just manifesting as a carb problem. Maybe it needs crank seals, reeds, or something. But before I learn through trial and error (and throw potentially unnecessary parts at it) I thought i'd seek out an internet forum that could hopefully make this easier.

Is this a common problem on these things? Is there an easy fix? What engine seals would affect fuel metering to this extent, and how hard are they to change? Is there something in the carb that I'm overlooking? Is it common practice to pressure test these motors, and if so, what kind of pressure should I expect it to hold for how long?

As far as I can tell, the machine is stock except for a missing air box.
 
I do have the air box and did manage to wrestle it into position once. It's not the problem. I even went out and bought the boots between the air box and carbs. It made no difference. I promptly removed the air box to re-jet and didn't put it back in because it appears to add little to no value. Just makes it a pain in the rear to pull the carbs. I also had to get it out of the way to get to the fuel pump - I replaced the lines (including the pulse line) to the pump, previous owner replaced the pump (probably for the same problem).

The restriction caused by the airbox is nowhwere near enough for it's removal to lean it out so much that increasing the jet size can't compensate. I went up a LOT in the jet sizes. One would expect to need the next higher jets with the air box removed - I went about 8 sizes higher. Went from like 140-somethings to 170's and it's still not getting the fuel it needs up top.

I don't plan to put it back in. I'm not worried about air filtration on a $300 machine and if I can figure out the fueling problem I can always leave it jetted up a bit to compensate.
 
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yeah an airbox would probably be a good idea... i dont know why so many people insist on taking them off... also spray some starting fluid around places that you think it could be sucking air... like the intake boots and the crankseals..... if it reacts to the starting fluid then you have an air leak there... also make sure you put those rubber plug(s) in the bottom of the main jet/ pilot jet area in the right holes... i believe the one with the the pilot jet actually needs plugged
 
I put the rubber plugs back in - not sure what they really do but I did put them back. Hopefully in the right holes! It's been a while since I had the carbs apart.

I'll try the starting fluid trick. I'm betting it's an air leak somewhere. I don't think it's the carb boots though.

Are the crank seals accessable? Where do I spray the starting fluid to get it to the crank seals? How far down do I have to take the motor to replace them? Bad crank seals is kind of what i'm betting on... an air leak is really the only explanation for why it wouldn't respond to jetting changes.

I have a .pdf manual for a 90+ phazer, it looks to be the same as my '85. Looks like I have to separate the crankcase to replace the middle seal, then there are two on the ends that don't look too bad... is that the case?

Also... where's the best place to get parts for these things? Looks like the bearing I need to replace is $70 and the housing for the bearing is $40... ouch!
 
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I ran it tonight and tried the trick with the starting fluid. Didn't tell me anything. Did manage to smoke out the garage though - I guess the oil injection works okay.

I don't think I could get any starter fluid down by the crank seals, so this doesn't rule those out.

I did a compression check and got 130 on one cylinder, 125 on the other. Looked into the cylinders with a scope and didn't see any piston wash, but did see signs of either rust on top of the piston or more likely detonation. Didn't see any missing chunks, so that's a good sign. I stuck the scope through the carbs and took a look at the reeds, they looked okay, all the petals in place and no apparent cracks or burnt spots.

So, next step pressure test? Probably need to just pull the motor and go from there, huh? Any better ideas before I yank it out?
 
That should have 2 Mikuni B38-32 butterfly's on it. Describe (in detail) what you did when you cleaned the carbs. Did you note what main jets, pilot jets, and air jets are in it? Where was the rubber plug (which hole)? How many turns was the pilot screw out? Where are the floats set at?

If you spray starter fluid behind the primary and near the rope entry for the recoil it will pick it up if it has an air leak. You will notice a surge in the engine speed at idle.

I suspect problems still in the carbs or electric.
 
hmm... describe in detail, now you're asking a lot!

I'll have to dig into them again to see what's in them. I do recall there being 2 rubber plugs in each carb though. I just pulled apart as much as I could without f'ing anything up and made sure everything was good and clean. I've learned a lot more about carbs over the summer though (blew up my waverunner, had to rebuild 3 mikuni SBN 44's, re-jet, check pop-off, etc) so maybe if I take them apart again i'll see something I didn't notice before.

I've been looking at the manual... all the seals in the bottom end are called "oil seals"... will any of them let air in to the point of causing this kind of problem?
 
Yes, Oil in - Air out . . .

However, from what you describe I just can't believe it is an air leak.

One test that used to be in the Skidoo manuals, was a crankcase leakdown test. Basically you plug off all the holes and put 5-7 psi of air in the crankcase and check for leaks. Soapy water in a spray bottle works real well for this. On a Phazer this is a relatively easy test. Pull the air shroud off, the carbs, the exhaust pipe, and the pulse line. Plug and seal all of these holes off. Rig up an adapter for a hand air pump with a pressure gauge to fit the spark plug holes. I use a hose off a compression tester with a quick disconnect on it, and spare air compressor fittings.

Be sure to only put low pressure (5-7 psi) in as you do not want to blow the crank seals.


Once you have it pressurized wait and check for dropping pressure. If it drops use the soapy water spray to find where the leak is (it will bubble up). Yo may need to check your plugs to make sure they aren't leaking.

This may keep you from tearing the engine down unecessarily. Of course it might be a good time to rebuild it anyway, but if you are trying to keep costs at a minimum, I would test first.
 
Yea I did that test on my GPR (waverunner) motor. I just regulated shop air down and pumped it in the pulse line. Left the spark plugs in place. Shut off a valve and waited for it to drop.

Thing is - I'd be surprised if I DON'T have at least a small air leak somewhere in the motor, but that doesn't mean an air leak is the cause of my problem. And I still can't see the crank seals to spray soapy water on them.

I'll pull the carbs off next time I wrench on it, and see if I can't rig it up to do a pressure test. I found the most difficult part was "plug all the holes"!
 
sleeper_dave said:
I found the most difficult part was "plug all the holes"!
Click to expand...
Yes, and they usually leak a little the first try.

Heavy plate drilled to match the bolt holes with a rubber gasket seems to work the best.

I use the regulator method too, but don't suggest it to others because it could easily go wrong and blow the seals out.
 
I don't have the equipment to quickly and accurately cut metal plates, so what I did with my waverunner was cut rubber sheets and pieces of ABS plastic to go over the reeds then bolted the carb over them to hold them in place. It took me a while to figure out what to do about the exhaust, but I ended up jamming a rubber pipe cap in there backwards then jamming a blackstone oil analysis cup in it to expand it. I shot the blackstone cup across the garage twice before I grabbed a ratchet strap to hold it in. Fun times.

I'll look at the carbs more closely and check the wiring a little more critically next time too. I know there is some electrical thing bypassed in there, I don't recall what it was though.
 
What does the switch on the throttle at the carb do? Looks like the switch is depressed at idle and released when you give it gas. It's bypassed on this one.

Pulled the carbs yesterday. Found that one of the starter enrichment jets froze up over the summer. I guess that's what happens when you don't do anything prior to storage. Oh well, it's free now, i'll clean it up and it'll be fine. On to a pressure test!
 
im not positive about the phasers but if they are like other sled then that is the TORS switches.... if the thumb throttle is closed and the carbs are still open it kills the spark....
 
It passed a pressure test. Held 6.5 psi for 40 minutes before I pulled the gauge off. So I guess I don't have to take anything else apart except the carbs.

There was a significant leak when I started, at the crossover between the two carb boots. There were no clamps on this part when I got the sled, and it seems it may need them. It would still build up to the regulated pressure, but when I closed off the air supply it would leak down pretty fast. I will add clamps there and keep a little grease on the crossover so that it stays sealed to correct this. Zip ties and some grease held it fine for the pressure test. I'm sure this was a contributor to my carb problems, but it probably wasn't the only cause.

Next step is going through the carbs a little more carefully. Anyone know if I can buy a rebuild kit for them? There wasn't much that I could really get to on them. Or, anyone have a known good set to sell cheap?
 
Also, anyone else have an idea what the switch on the carb is? I can't find any mention of it in the manual, and i'm not seeing another switch on the thumb lever to indicate that it's the TORS that Tyler mentioned.
 
;)! this has not been [phazed] out yet?.the 2 low speeds adjustments on top of carbes by intak between jug & cabe set them 2 turne out.the t.o.r.s. you can bypass.the wires on carbe the 1 going to the carbe connect them together that complets the cuicrt.good luck i bougt 2 phazers 2 or 3 yrs a go for $100. 1 good motor/ 1 nice sled/ sold junk 1 for $50.the wife is haveing fun.it is just somthing SMALL? ;)!
 
Yep, that's the TORS switch. If you want to bypass the TORS switch simply connect the two leads that that go to the carb together. With the leads connected to each other you are short circuiting and eliminating the TORS switch. The TORS switch is talked about in the Clymer manual for the Phazer for your reference
 
That being said, I wouldn't recommend bypassing the TORS switch. It is an important safety feature, especially if someone other than yourself will ever by riding. I have had the throttle stick, and if you aren't on your toes and use the kill switch you are in for a wild ride.
 
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