94 Waverunner III - troubles continue...please help!

robcarync

Petty Officer 3rd Class
Joined
Aug 19, 2010
Messages
82
I made a post earlier regarding what I thoght was the troubles...have fixed a few things and I still can't get this WR III going properly.

I just replaced all the gaskets on the intake side, inspected reed valves while I was down there, and everything looks good. (there was a huge air leak below the carbureuter)

I have replaced fuel filter, all fuel lines, checked the fuel tank check valves and that all looks to be good.

I also removed the spark plug boot and trimmed the wires back about 1/4 inch.

I replaced the fuel regulator diaphragm because the old one had a rip all around the edges of it. I did not completely rebuild the carb, but I inspected the fuel pump side, gaskets looked brand new, sprayed some carb cleaner through passages to verify they were not blocked and check valves operate as designed.

Here is the symptoms I am now having. The low end appears to operate as dsigned. It picks up pretty well with no misfires and will run up to half throttle.

In the water and out of the water, once I give it more gas, it begins to mis and sounds like the engine pulses. There is absolutely no power past half throttle. Here is an interesting note: bringing the high end adjuster out (out a lot...as in very rich) the pulsing/misfires seem to go away, but there still isn't power or any more speed.

For comparison, I brought the low end speed screw out about 1 full turn and it started to run really rough and bog down. (I then put the low end screw back to spec) I just found it interesting that bringing the low end screw out a turn made it run terrible, but bringing the high end screw out nearly 3 turns did not have the same affect...actually made the engine sound/run better, just still no top end power.

I have not looked at the high end jet as the two screws that hold the cover on are rounded out right now, but does it sound like it may be a faulty high end jet or check valve?

Could it be an electrical problem?

The fact that it runs great up until about 1/2 makes me think it has to be carb related...at around half is where the high speed jet comes in....and from 3/4 to full is where the high end screw comes in.

My thinking: A clogged high speed jet could cause it to miss...as the top end would be lean. Opening up the high end jet would let more fuel by since the jet is clogged...making the engine seem to miss less as it kind of compensates for the lack of fuel at the jet. Does this make sense? I haven't done much work on ski's before so I could be mising something here.

I thought for sure the ripped up diaphragm would be the cause but now I am starting to wonder if I can ever get this thing running properly!

Also, on a side note, the fuel lines are 3/16 of an inch...but I did not have enough so two lines are 1/4 inch (going from selector valve to fuel filter, to carb) I would not think that having 2 different diameter fuel lines would make much of a difference (given its only 1/16 of an inch difference) but I made sure to zip tie them down so no air leaks out at the junctions.
 

The Penguin

Petty Officer 2nd Class
Joined
Mar 16, 2010
Messages
138
Re: 94 Waverunner III - troubles continue...please help!

how many times do I have to suggest a complete rebuild of the carb?

since the first day you posted about this ski, the carb has been been suspect.

you had it a apart just a few days ago.

take it back off, completely disassemble it, clean it, inspect it thoroughly, and reassemble it with new parts.

or, you could keep jacking with it for ANOTHER month.

oh, and change out the fuel lines to the proper size. 1/4" fuel line is available at most auto parts stores.
 

robcarync

Petty Officer 3rd Class
Joined
Aug 19, 2010
Messages
82
Re: The hearts

Re: The hearts

I guess it is because I think I have narrowed it down to behind the two F*d up screws by the needle and seat and I don't want to start hacking away at them unless someone else thinks it is right...plus just for my own curiosity I'd like to understand what specific parts cause the issue...not a shotgun understanding "oh my ski ran rough on the top end so I rebuilt the carb"

The proper size is 3/16 not 1/4. I used 2 strands of 1/4 inch lines because 3/16 did not fit on the fuel filter section.

And I haven't jacked with it a month...It is not with me so I get to see it a weekend at a time if I make it to the beach for the weekend, which has been 1 of the last 3 weekends. My other 18 days of the last three weeks have been occupied with grad school and work.
 

The Penguin

Petty Officer 2nd Class
Joined
Mar 16, 2010
Messages
138
Re: 94 Waverunner III - troubles continue...please help!

I'm fairly certain that 1/4" is the correct size. I'd have to measure some of the extra I have at home to be sure, but I just checked the website where I purchased it from and they don't sell fuel line in 3/16. I know many people have ordered fuel lines from this same site, so I know I'm not alone in using only 1/4" in my skis.

the part you can't remove is call the "metering plate" if my memory is correct. There is a small check valve on the back side of it that should be replaced, and of course both jets are behind it also. there are also 2 larger check valves on the fuel pump side - did you replace them?

the impact screwdriver I mentioned should make quick work of those 2 screws. You can get stainless steel replacement screws (M4x12mm, I think) with a hex head at almost any Ace Hardware store. the screws they sell are a bit longer than stock, but don't worry - they thread in fine and the longer threads don't affect anything internally.
 
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