Bonmotwang
Well-Known Member
Do I out the fuel pump on to do the pop off test on the MAG carb?
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2001 Seadoo Sportster LE. Just got it!
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Bonmotwang
Well-Known Member
Thanks. Ok. Going slowly. Do I need to block the fuel inlet from the fuel tank?
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Bonmotwang
Well-Known Member
Sportster-2001-951C-Stock
Well-Known Member
Reference the Mikuni table, pop for 95gr spring and 2.0 orifice should give you ~25psi
I think it's okay to have within 2 psi less (23psi) but try to make carb A and carb B pop within 1 psi if possible.
My black spring popped at 21psi, just as the table said it would.
Sportster-2001-951C-Stock
Well-Known Member
You need to block both ends of the fuel return orifice "T" and the fuel feed to PTO carb.
You cleaned both return orifces using carb cleaner and air sprayed backward through it, right? Don't use a wire for this, or make the mistake of thinking it's restricted (it's supposed to be restricted) and then try to open the restriction by drilling it.
You can block the pulse line (optional) to avoid POSSIBLE damage to fuel pump diaphragm. I didn't block mine, and didn't see any damage to diaphragm. Air should not leak from the FP diaphragm pulse fitting unless the diaphragm is damaged with a hole in it.
You cleaned both return orifces using carb cleaner and air sprayed backward through it, right? Don't use a wire for this, or make the mistake of thinking it's restricted (it's supposed to be restricted) and then try to open the restriction by drilling it.
You can block the pulse line (optional) to avoid POSSIBLE damage to fuel pump diaphragm. I didn't block mine, and didn't see any damage to diaphragm. Air should not leak from the FP diaphragm pulse fitting unless the diaphragm is damaged with a hole in it.
Bonmotwang
Well-Known Member
OK, three fingers for blocking. I did the test.
Because I did it very slow. it didn't pop. only leaks. did 3 times. leaks at 24PSI.
I didn't block the pulse line, and it holes the pressure very well during the test.
You probably didn't realize that I put all the old the parts back for the pop off test. New kits are still in the package
I just wanted to know what I had there.
So the history on the carbs was:
PTO with the compressed spring: 15/16PSI
MAG with the good spring: 24/25PSI
Put good spring into PTO carb, the pop off went back to 24/25PSI.
So with one side low PSI, what will it affect the performance? Or and link to the piston scoring :-D ?
Sportster-2001-951C-Stock
Well-Known Member
The weak spring will just cause more fuel at low speed, not sure which carb you found it in, maybe PTO. So this kinda offsets the gasket air leak, but it's not a good way to tune any carburetor, LOL!
I think there is a history of plugged carbs and lean running the PO tried to fix that may have caused rapid wear but remember, these engines reportedly puke their guts before 300 hours anyway. Carb problems of too lean or very rich (lubrication washed away by fuel) brings quicker death, and can be the root cause of seizure. Your motor appears to have suffered multiple seizure syndrome (witness considerable aluminum transfer on cylinder liner).
Seizure is what happens when they wear out though, and we have no idea of how many hours are on this engine (I have no idea of how many hours on mine either), so write us a macro string for our terminal program so we can retrieve the engine hours from the MPEM!
I think there is a history of plugged carbs and lean running the PO tried to fix that may have caused rapid wear but remember, these engines reportedly puke their guts before 300 hours anyway. Carb problems of too lean or very rich (lubrication washed away by fuel) brings quicker death, and can be the root cause of seizure. Your motor appears to have suffered multiple seizure syndrome (witness considerable aluminum transfer on cylinder liner).
Seizure is what happens when they wear out though, and we have no idea of how many hours are on this engine (I have no idea of how many hours on mine either), so write us a macro string for our terminal program so we can retrieve the engine hours from the MPEM!
Sportster-2001-951C-Stock
Well-Known Member
24psi is good, I think. Once the leaking begins then at what pressure does it stop leaking?
Bonmotwang
Well-Known Member
Dose seizure necessary mean totally stuck? Do you have a MPEM schematic? Easy enough to make a simple milage meter.
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Bonmotwang
Well-Known Member
I took it apart again. Will do the stop leak test when I put the new set in.
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Sportster-2001-951C-Stock
Well-Known Member
This is a dialog from an ELM-327 AT session, we need this for the Seadoo MPEM, so get busy on this project!
>at h1
OK
>at d1
OK
>at sh 79b
OK
>at fc sh 79b
OK
>at fc sd 30 00 20
OK
>at fc sm 1
OK
>21 02
7BB 8 10 C6 61 02 0F C6 0F CD
7BB 8 21 0F CC 0F C4 0F D5 0F
7BB 8 22 D1 0F CB 0F C4 0F D1
7BB 8 23 0F C6 0F C8 0F C4 0F
7BB 8 24 D2 0F D6 0F D2 0F D3
7BB 8 25 0F D2 0F C8 0F C8 0F
7BB 8 26 C9 0F D2 0F C8 0F CD
7BB 8 27 0F C4 0F D1 0F CD 0F
7BB 8 28 CC 0F C8 0F CD 0F D2
7BB 8 29 0F CD 0F D2 0F CF 0F
7BB 8 2A CF 0F D4 0F D2 0F C6
7BB 8 2B 0F CB 0F CB 0F C8 0F
7BB 8 2C C4 0F C4 0F C8 0F C4
7BB 8 2D 0F D1 0F CF 0F D5 0F
7BB 8 2E D1 0F CF 0F D1 0F D5
7BB 8 2F 0F C8 0F D4 0F D0 0F
7BB 8 20 D4 0F D1 0F D7 0F D2
7BB 8 21 0F C8 0F CD 0F C3 0F
7BB 8 22 D2 0F C9 0F CE 0F C4
7BB 8 23 0F CD 0F C4 0F C8 0F
7BB 8 24 CD 0F CD 0F CD 0F CD
7BB 8 25 0F CC 0F CC 0F CB 0F
7BB 8 26 C8 0F C4 0F CD 0F C3
7BB 8 27 0F C9 0F CF 0F CF 0F
7BB 8 28 D5 0F CD 0F D5 0F D1
>at h1
OK
>at d1
OK
>at sh 79b
OK
>at fc sh 79b
OK
>at fc sd 30 00 20
OK
>at fc sm 1
OK
>21 02
7BB 8 10 C6 61 02 0F C6 0F CD
7BB 8 21 0F CC 0F C4 0F D5 0F
7BB 8 22 D1 0F CB 0F C4 0F D1
7BB 8 23 0F C6 0F C8 0F C4 0F
7BB 8 24 D2 0F D6 0F D2 0F D3
7BB 8 25 0F D2 0F C8 0F C8 0F
7BB 8 26 C9 0F D2 0F C8 0F CD
7BB 8 27 0F C4 0F D1 0F CD 0F
7BB 8 28 CC 0F C8 0F CD 0F D2
7BB 8 29 0F CD 0F D2 0F CF 0F
7BB 8 2A CF 0F D4 0F D2 0F C6
7BB 8 2B 0F CB 0F CB 0F C8 0F
7BB 8 2C C4 0F C4 0F C8 0F C4
7BB 8 2D 0F D1 0F CF 0F D5 0F
7BB 8 2E D1 0F CF 0F D1 0F D5
7BB 8 2F 0F C8 0F D4 0F D0 0F
7BB 8 20 D4 0F D1 0F D7 0F D2
7BB 8 21 0F C8 0F CD 0F C3 0F
7BB 8 22 D2 0F C9 0F CE 0F C4
7BB 8 23 0F CD 0F C4 0F C8 0F
7BB 8 24 CD 0F CD 0F CD 0F CD
7BB 8 25 0F CC 0F CC 0F CB 0F
7BB 8 26 C8 0F C4 0F CD 0F C3
7BB 8 27 0F C9 0F CF 0F CF 0F
7BB 8 28 D5 0F CD 0F D5 0F D1
Sportster-2001-951C-Stock
Well-Known Member
Seizures can be partial, this is most common unless the engine is severely beyond operating parameters such as no cooling water, too lean or no XPS2 oil and in that case seizure is more likely to become a permanently stuck motor.
A stuck motor sometimes unsticks once it cools off to ambient temperature, then it can be restarted again but it won't last long due to the damage.
Once aluminum is melted onto the cylinder liner it further interferes with ring sealing and causes increased combustion gas blow-by, this leads to a snowball effect until something breaks or sticks permanently.
If there is aluminum on the cylinder wall, the top end should be rebuilt at a minimum and the piston tolerance checked/adjusted to return this to spec.
Straight-gassing a 2-stroke is a great way to ruin it.
Bonmotwang
Well-Known Member
So it makes sense that too much fuel got into the PTO cylinder and washed off the oil, and causing more wear than the MAG?
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Sportster-2001-951C-Stock
Well-Known Member
Too much fuel caused PTO damage? I doubt this, I'm more inclined to think a lean fuel mixture may have accelerated the wear (if anything). The reasons I think this are several:
1) The PO was forced to rebuild the carbs b/c they were plugged with "tempo trash" and running lean. (Lean = quick engine damage in a 2-stroke just as WAY too rich fuel ratio to oil can lead to slow death)
2) The gasket air leak didn't help, once the carbs were rebuilt the mixture may have been too lean as a result of an air leak.
3) Pop pressure has most effect during low speed operation and idle, the engine isn't developing much heat under these conditions thus aluminum is unlikely to melt and become damaged as long as some oil is in the crankcase. There is no oil coming from the injection pump during idle b/c the oil remaining in the bottom of crankcase is enough unless the crankcase is being flooded with fuel and the oil is washed away. In this case the spark plug will become wet with fuel and stop firing.
This is why I asked if there was oil still in the crankcase, b/c there would be only a small amount or maybe zero oil, if the carb was washing the fuel away. Always look inside the crankcase to see if there's enough oil!!!
And I think the motor wouldn't idle very well with this excess amount of fuel in PTO crankcase b/c the spark plug could not fire if it's wet and drowned with fuel.
15psi of pop is borderline too low IMO, and you might not notice it's a little too rich unless the motor loads up with fuel and PTO stops firing. To notice if it's too rich allow motor to idle for a few minutes and the crankcase will load up with fuel, then the plug will become wet and stop firing. So combine that with an air leak from the damaged gasket and maybe it offsets the mildly rich condition but now it's actually too lean at idle and not washing oil away but may run away on the trailer due to being lean, instead of too rich?
If a 2-stroke cylinder is not receiving fuel, it also isn't receiving oil lubrication normally b/c the fuel carries the oil throughout the crankcase and into the cylinders. A good amount of this oil sits down in the crankcase with the rotating assembly and comes from oil dropping out of the fuel as it travels through the crankcase on it's way to the cylinder. But, the crankcase can only hold a certain volume of oil before the oil begins slinging upward into the cylinders and back into the fuel where it's carried into the cylinders to be burned.
By this you can imagine the advantages and disadvantages of pre-mixing vs oil injection:
Oil injection provides a safety measure of providing oil even if the carb is plugged and not flowing fuel+oil (but it's only a partial solution to lack of lube due to plugged carbs).
Pre-mixing strategy is dangerous from the perspective if the carb is dry due to plugging of fuel passages then no oil is delivered to the cylinder, maybe zero oil!
Pre-mixing avoids the problem of oil injection system failure due to lack of proper maintenance or other problems that might occur such as a broken oil line.
Oil injection helps to conserve oil via the variable oil rate. It's unnecessary to have rich oil conditions at low speeds due to the engine is not making maximum heat.
Pre-mixing requires the carburetor to be recalibrated richer to deliver more fuel b/c the mixed oil displaces fuel while traveling through the carburetor jets. To compensate, the jets must be slightly larger by the percentage of oil mixed.
With a little imagination, you can perhaps add to this comparison list.
1) The PO was forced to rebuild the carbs b/c they were plugged with "tempo trash" and running lean. (Lean = quick engine damage in a 2-stroke just as WAY too rich fuel ratio to oil can lead to slow death)
2) The gasket air leak didn't help, once the carbs were rebuilt the mixture may have been too lean as a result of an air leak.
3) Pop pressure has most effect during low speed operation and idle, the engine isn't developing much heat under these conditions thus aluminum is unlikely to melt and become damaged as long as some oil is in the crankcase. There is no oil coming from the injection pump during idle b/c the oil remaining in the bottom of crankcase is enough unless the crankcase is being flooded with fuel and the oil is washed away. In this case the spark plug will become wet with fuel and stop firing.
This is why I asked if there was oil still in the crankcase, b/c there would be only a small amount or maybe zero oil, if the carb was washing the fuel away. Always look inside the crankcase to see if there's enough oil!!!
And I think the motor wouldn't idle very well with this excess amount of fuel in PTO crankcase b/c the spark plug could not fire if it's wet and drowned with fuel.
15psi of pop is borderline too low IMO, and you might not notice it's a little too rich unless the motor loads up with fuel and PTO stops firing. To notice if it's too rich allow motor to idle for a few minutes and the crankcase will load up with fuel, then the plug will become wet and stop firing. So combine that with an air leak from the damaged gasket and maybe it offsets the mildly rich condition but now it's actually too lean at idle and not washing oil away but may run away on the trailer due to being lean, instead of too rich?
If a 2-stroke cylinder is not receiving fuel, it also isn't receiving oil lubrication normally b/c the fuel carries the oil throughout the crankcase and into the cylinders. A good amount of this oil sits down in the crankcase with the rotating assembly and comes from oil dropping out of the fuel as it travels through the crankcase on it's way to the cylinder. But, the crankcase can only hold a certain volume of oil before the oil begins slinging upward into the cylinders and back into the fuel where it's carried into the cylinders to be burned.
By this you can imagine the advantages and disadvantages of pre-mixing vs oil injection:
Oil injection provides a safety measure of providing oil even if the carb is plugged and not flowing fuel+oil (but it's only a partial solution to lack of lube due to plugged carbs).
Pre-mixing strategy is dangerous from the perspective if the carb is dry due to plugging of fuel passages then no oil is delivered to the cylinder, maybe zero oil!
Pre-mixing avoids the problem of oil injection system failure due to lack of proper maintenance or other problems that might occur such as a broken oil line.
Oil injection helps to conserve oil via the variable oil rate. It's unnecessary to have rich oil conditions at low speeds due to the engine is not making maximum heat.
Pre-mixing requires the carburetor to be recalibrated richer to deliver more fuel b/c the mixed oil displaces fuel while traveling through the carburetor jets. To compensate, the jets must be slightly larger by the percentage of oil mixed.
With a little imagination, you can perhaps add to this comparison list.
Bonmotwang
Well-Known Member
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Bonmotwang
Well-Known Member
He got it done 30 minutes ago. Looks good.
yes, 0.5mm, I guess I misread his email. He said 0.025" :-D
He did 0.25mm, then the lines are still there, so 0.5" did it.
He kept telling me at least 3 times and wrote it down on the box, "Arrow to the exhaust!!!"
I will bring in the Raves in the morning and he will trim it down for me.
yes, 0.5mm, I guess I misread his email. He said 0.025" :-D
He did 0.25mm, then the lines are still there, so 0.5" did it.
He kept telling me at least 3 times and wrote it down on the box, "Arrow to the exhaust!!!"
I will bring in the Raves in the morning and he will trim it down for me.
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Waterluvr
New Member
Did you get assembly gaskets from him as well? You could have that all back together and running tonight if you get busy.
I think I would probably pop the c-clip out of the drive shaft and let the bellows and carbon seal relax in order to run it on the hose for a little while once it's all together.
I think I would probably pop the c-clip out of the drive shaft and let the bellows and carbon seal relax in order to run it on the hose for a little while once it's all together.
Bonmotwang
Well-Known Member
Yes, I got the gaskets. not in the picture.
I cannot wait! but I need him to trim my Raves in the morning.
We briefly talked about the how this happened. He is basically saying mostly normal wear over the 13 years of operation. For those vertically line, he mentioned water got injected into the cylinder and washed the oil away.
Anyway, now all new. Either tonight or tomorrow morning, I will put the top end back.
Will pick up another gallon of XPS II for the fuel tank premix. I already got 8/10 tank of gas there. Is it going to mix well if I just put in the oil without suck out the fuel?
For the C Clip. I read in the forum it is a pain to get it out. And I found another(?) C Clip in the bilge a few weeks ago :-D
Is it better to break it in in the water? Or you just meant on hose for 2, 3 minutes?
I cannot wait! but I need him to trim my Raves in the morning.
We briefly talked about the how this happened. He is basically saying mostly normal wear over the 13 years of operation. For those vertically line, he mentioned water got injected into the cylinder and washed the oil away.
Anyway, now all new. Either tonight or tomorrow morning, I will put the top end back.
Will pick up another gallon of XPS II for the fuel tank premix. I already got 8/10 tank of gas there. Is it going to mix well if I just put in the oil without suck out the fuel?
For the C Clip. I read in the forum it is a pain to get it out. And I found another(?) C Clip in the bilge a few weeks ago :-D
Is it better to break it in in the water? Or you just meant on hose for 2, 3 minutes?
Waterluvr
New Member
I'd run it for a few minutes, then shut it off and head for the water. A thin flat blade screw driver will get under it and pop it right up and off there. I know they say you can run it for a few minutes as is but I don't see how it doesn't destroy the o-rings in the stainless carrier almost immediately when run dry.
Keep that extra clip handy as a spare on board if the one in the shaft groove ever failed for some reason and you had water gushing in that would save the day.
Keep that extra clip handy as a spare on board if the one in the shaft groove ever failed for some reason and you had water gushing in that would save the day.
Bonmotwang
Well-Known Member
Double checking: when I use the new gasket do I need to put silicon or liquid gasket on them? Or just dry assembly?
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Bonmotwang
Well-Known Member
Hasn't started yet. Just making sure I get my mind straight for every step. Probably do it in the morning so that I am not too tired. Is there any thing I need to be warned? Except don't drop anything into the crank case? I am obsessive on that now :-D
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