96 XP running rich at low speed

[harleytq]

So I bought this one last year, took it to the lake thinking it was a good running ski.
Started up great and idled good, but would just bog out. So I rebuild the carbs thinking that must be the problem, but no change at all.
So I then discovered the rectifier was bad and replaced that. So that was end of season, now I get it to lake and it runs rich at low throttle, but maybe 1/2 on up seems to run great and the plugs look good.
Then I discovered the exhaust valve leaking, I think I have that fixed now, is that supposed to supply water at all rpms to the pipe? pulled hose at idle speed and it was spraying water, with no leaking under valve.
So then I thought maybe it just needed an 1/8 to 1/4 turn in on the Low speed screws, so I did go 1/4 in which would be screw at 3/4 turn out. still didnt run much better, and at that point I was afraid to turn the low speed screw in any more, there must be some other reason it is running crappy at low speeds.
I set the pop off in the right range, but is there any difference if you set it on the high side or the low side of pop off range? would that change my low speed fuel?
But then I wonder if it just isn't running right at low speed, maybe electrical or something and that's why my plugs are black? One of my other issues is when I hit the start button it takes a few seconds before it cranks the engine, but once it cranks it cranks fine and starts up good. It just has like a 5 -10 second pause, where you almost think it isn't going to crank the engine.
Should I replace the starter solenoid, for that problem? could I have other electrical issues causing the engine to run rough at low speed, but then runs great at high speed?
Any ideas would be appreciated,
I'm almost at the point of buying another one that runs right and switching parts. lol

 

[harleytq]

Just a little more background on this.
previous owner sucked up rocks in the impeller and bent the crap out of it, I keep wondering if that could have screwed something up, making this thing run like crap.
Also P.O. said he was having a problem with it running rich, and disconnected the oil injection and went to premix, thinking it was getting to much oil. Pretty sure he said that fixed the problem, but I guess not.
Guess I should have ran from this one.
Funny thing is this thing actually looks really nice. Guess you cant always go by looks. LOL

 

[mikidymac]

First, are you still supplying oil to the rotary gear?

The screws should be set to the book settings.

I am not sure how you set the pop-off to the end of the range but you need to have the correct needles and seats (hopefully new and genuine mikuni), the correct springs (80 gram, not the ones in the rebuild kits) and needle arms that are not bent. Pop-off should be fast, clean and not leak at all after it pops. The carbs have to hold pressure after putting back together to verify no needle and seat leaks.

 

[harleytq]

First, are you still supplying oil to the rotary gear?

The screws should be set to the book settings.

I am not sure how you set the pop-off to the end of the range but you need to have the correct needles and seats (hopefully new and genuine mikuni), the correct springs (80 gram, not the ones in the rebuild kits) and needle arms that are not bent. Pop-off should be fast, clean and not leak at all after it pops. The carbs have to hold pressure after putting back together to verify no needle and seat leaks.

Yes the rotary valve still has lines connected.
The pop off was 38 if I remember correctly.
Yes it was a rebuild kit from OSD, with new needles and seats.
The only thing I didn’t change were the needle arms, I guess I assumed they were good because I got an acceptable pop off valve.
I did pressurize the carb, to 10 psi I think you said in your carb rebuild thread. It looked good doing that also.
Do I want a lower pop off valve, or doesn’t that matter?

 

[mikidymac]

No, pop-off will not matter.

Compression numbers?

 

[harleytq]

No, pop-off will not matter.

Compression numbers?

Compression is good 150 on both.

 

[POPPS]

Maybe the needles and seats are leaking?…but weak compression can easily cause your issues,,.load test the battery as well.

 

[harleytq]

Maybe the needles and seats are leaking?…but weak compression can easily cause your issues,,.load test the battery as well.

So you are saying it might run rich at low speed if the needles and seats were leaking? They are new, but suppose it could leak around the outside of the seat, maybe there's damage or corrosion where the O ring sits?
Tried 2 different batteries for the starting issue, a good one from my 95 XP, which always cranks good. Put other battery in 95 and that still worked great.

 

[harleytq]

Was out of town for the weekend.
So is that pretty much the only thing it could be, something with the carbs?
Like Popps said maybe the new needle and seats are leaking? Could it be just because I didn’t use the new arms for the needles?
Or maybe something plugged in carbs? But would that make it lean?
Is there anything else that could have got screwed up, if the Previous owner tried to jump start it? Could the new rectifier still not be completely right?

 

[Lothsahn]

If something was plugged in carbs, I would expect it to run lean, not rich.

Just wanted to confirm again--when you did the rebuilt, you used the ORIGINAL springs, not the new ones that came in the kit, right? The ones that came in the kit are wrong. You have to reuse the original springs.

If it's running rich, I would suspect something is wrong with the carbs.

Are both cylinders running rich or just one? How do you know it's running rich?

 

[harleytq]

If something was plugged in carbs, I would expect it to run lean, not rich.

Just wanted to confirm again--when you did the rebuilt, you used the ORIGINAL springs, not the new ones that came in the kit, right? The ones that came in the kit are wrong. You have to reuse the original springs.

If it's running rich, I would suspect something is wrong with the carbs.

Are both cylinders running rich or just one? How do you know it's running rich?

Well I used the springs in the kit, it’s not the mikuni kit, it’s the OSD Marine kit, called the Back to OEM kit, they say they supply 2 new OEM mikuni springs. They are kinda black in color if I remember correctly. I could very well be wrong, you guy’s probably know more than I do?
As far as it running rich, I putted around a little bit and then checked plugs, they were a little wet and black. Could possibly be something else, maybe electrical? Seems to kinda run a little rough or kinda misses on takeoff, for sure it doesn’t have good performance from takeoff, my 95 xp would toast this thing out of the hole. Plugs looked great after higher speeds.
Both cylinders looked the same.

 

[mikidymac]

OSD kits have the correct springs.

Try unplugging the red wire from the voltage regulator. This will see if it is bad but your battery will not be charging. It’s really common on these and can cause all kinds of strange running issues.

 

[Lothsahn]

Miki, you're probably right, but I rebuilt two sets of carbs and I could swear that my OSD kits came with the wrong springs. OSD does let you order individual springs.

Rectifier is a good suggestion. Usual failure mode is at high rpms, not low, but it's a good thing to check. I've had 2 fail in 3 years.

 

[harleytq]

OSD kits have the correct springs.

Try unplugging the red wire from the voltage regulator. This will see if it is bad but your battery will not be charging. It’s really common on these and can cause all kinds of strange running issues.

I will try that this weekend, but this was a new rectifier. But I guess it could still be bad.

 

[harleytq]

OSD kits have the correct springs.

Try unplugging the red wire from the voltage regulator. This will see if it is bad but your battery will not be charging. It’s really common on these and can cause all kinds of strange running issues.

I unplugged the red wire this weekend, in the process of doing that I disconnected a couple wire plugs, one was the stator on front of engine. Anyway as soon as I hooked the 2 wires plugs back up, my beeper started working again. So I took it for a ride and it seemed to be running good, except for a little hesitation on the 1st take off, but that seemed to go away after it warmed up. Came back hooked the red wire back up and it still seemed to be running good, and beeper was still working. Left it sit for a while, came back and no beeper again. I thought dang it, went and disconnected red wire again, still no beeper, so I hooked up the red wire and took it for a ride. Seemed to still be running good, just no beeper anymore.
So maybe it was just a bad connection, I've read a few posts talking about problems with stator pickup coil or something. should I pull the front cover to see what it looks like in there? or call it good?
One thing I did notice is water leaking from exhaust manifold and head pipe gasket. Bolts are tight, does the gasket just shrink up or something. could that be causing any problems?

 

[harleytq]

So at the end of the day, I feel like I have something leaking air into the pump, Really seems to be slipping on take off, or not hooking up.
I think the carbon seal is working, but if it were leaking, at what speed would it tend to leak?
I had the pump off this spring to replace the impeller, maybe that isn't sealed up good, used the neoprene seal and siliconed the 3 water fittings. should I check the ride shoe?
The previous owner had an aluminum pump from like a 92 I think, but now I changed it back to a stock pump, would I have to change anything else when doing this, are all the driveshafts the same length? well I guess thats a dumb question, because he still had the carbon seal setup.
Tried to do some wide open runs, was getting around 6600 rpm, seems like that might be a little low?
Didn't have gps to get speed, what are you guys using, a gps app?

 

[harleytq]

So I've been reading about the exhaust leaking,
and HOW IT CAN LEAK INTO THE ENGINE.
Thanks for the heads up on that, If anyone is reading this stuff?

 

[mikidymac]

It doesn't "leak into the engine". It can leak into the engine compartment from a burnt hose or bad gasket and the exhaust is in the engine compartment. This takes up the oxygen the engine needs to burn and chokes out the engine.

 

[harleytq]

It doesn't "leak into the engine". It can leak into the engine compartment from a burnt hose or bad gasket and the exhaust is in the engine compartment. This takes up the oxygen the engine needs to burn and chokes out the engine.

Here’s what I was reading.

Tech GuruPWCToday.com Is My Home Away From HomeJoin DateFeb 2004LocationGlendora, CaliforniaPosts25,271

Re: Gasket Sealant on Exhaust Gaskets?​

Why take the chance, especially on used parts such as clyinders and exhaust manifolds ?

Do you know what happens when the exhaust manifold leaks? It not only leaks externally and sprays water into the intake, but it leaks internally and water gets into the clyinders. When does all this take place? At very high rpm when the jetpump is producing the most water pressure in the cooling system. Does any of that sound like a good risk to you?

 

[harleytq]

[ATTACH=full]59783[/ATTACH]

nickj718​

Active Member​

• Aug 3, 2016
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• #12

Thank you everyone. I used a gasket before with no sealant and it failed. It was a paper gasket though. The paper part of the gasket deteriorates and water went right into the cylinder and killed the motor right away. Flooded it so bad I couldn't even get it running so that's why I asked. I guess if it's a paper gasket I would use some sort of sealant if need be but in this case I do not need to. I appreciate everyone's input.

This is exactly why i use a thin coat of exhaust sealant. I use it on all my builds and customers never had a problem and its so nice when you have to take it back apart. Just use your finger and spread a thin layer staying away from the cooling passages

 

[harleytq]

I don’t know, are they talking exhaust manifold leak, at engine?
Bottom line, I can’t figure out why nobody is willing to give me suggestions on anything to try.

 

[mikidymac]

They are mainly talking about the 951 engines as they can spray water from the pipe directly into the carbs.

What are you asking at this point?

Sounds like you fixed the running issues and are just dealing with cavitation now?

 

[harleytq]

They are mainly talking about the 951 engines as they can spray water from the pipe directly into the carbs.

What are you asking at this point?

Sounds like you fixed the running issues and are just dealing with cavitation now?

Well as far as the water leaking at manifold and head pipe, that wouldn’t cause any running issues?
Then the beeper all of a sudden working and then just stopping after red wire being connected again. Is there just no reason for that? Seems funny that the 1st time I disconnected the wire, last year, that the beeper started working again too. Should I try a different rectifier? Try the heavy duty one at OSD?
By the way, thanks for responding.
Sorry if I sounded a little upset, it just gets frustrating when nobody says anything.

 

[mikidymac]

Yes, a leaking exhaust manifold would cause issues but this is very uncommon on the 787 engines and if it is leaking typically it would be spraying water out where you can see it.

The beepers can be very glitchy and can come and go but typically they just quit. I have even had the OEM replacements just stop working out of the blue.

As long as it is running normally and the voltage numbers check out I wouldn't mess with the rectifier.

 

[harleytq]

Yes, a leaking exhaust manifold would cause issues but this is very uncommon on the 787 engines and if it is leaking typically it would be spraying water out where you can see it.

The beepers can be very glitchy and can come and go but typically they just quit. I have even had the OEM replacements just stop working out of the blue.

As long as it is running normally and the voltage numbers check out I wouldn't mess with the rectifier.

I am seeing some water coming out at the connection of manifold and head pipe, funny it almost seems to come and go, doesn't seem to be consistent. not a spray either. Or maybe its leaking on the bottom and I only see it come to the top sometimes, not sure.

Whats your thoughts on the air leak, would the carbon seal have to be leaking water to also affect the air in the pump. And when is the most likely time that they leak, idling, cruising, accelerating? I am getting some water in my bilge. Not exactly sure where its coming from.
How often do you see the ride shoe leaking air?