one cylinder no getting fuel.

[Sportster-2001-951C-Stock]

No And with it being that far off is probably why I can't get any fuel to the rear cylinder

Well dang, still doesn't sound good. Maybe the gas station can test your compression gauge, or autozone can test it but if compression is really down that much then at least the engine will need piston rings, maybe more.....

 

[richey]

Well dang, still doesn't sound good. Maybe the gas station can test your compression gauge, or autozone can test it but if compression is really down that much then at least the engine will need piston rings, maybe more.....

Yea I really don't think my wife will let me spend another $300 on a rebuild kit. Lol she is already upset that I got it

 

[Sportster-2001-951C-Stock]

Yea I really don't think my wife will let me spend another $300 on a rebuild kit. Lol she is already upset that I got it

Hide it somewhere or bury it in the back yard, take it down the street and ditch it somewhere else, wives can get ugly about stuff like that!

But you already had your ski at the lake and it was running good until the starter stopped working, so it's hard to imagine what happened. Just some cranking on the trailer shouldn't hurt it so bad so fast, running without oil+fuel would damage just one cylinder, not both.

 

[richey]

Hide it somewhere or bury it in the back yard, take it down the street and ditch it somewhere else, wives can get ugly about stuff like that!

I guess my only question now is. Is this thing worth rebuilding or should I just cut my losses and junk it?

 

[Sportster-2001-951C-Stock]

I guess my only question now is. Is this thing worth rebuilding or should I just cut my losses and junk it?

Need to get a look at the cylinders and pistons, I guess. You just won't know till you get a good look inside, but if the RV crank seals are leaking then you'll need a bottom end too (for new crank seals), and the money spigot opens further, so pressure checking the RV cavity is first thing to do to move forward for sure.

 

[richey]

Need to get a look at the cylinders and pistons, I guess. You just won't know till you get a good look inside, but if the RV crank seals are leaking then you'll need a bottom end too (for new crank seals), and the money spigot opens further, so pressure checking the RV cavity is next thing to do for sure.

Now we r getting a little to technical. I am not a mechanic I know how to take stuff apart a put it back together but as far ad testing the RV cavity I think I might be out of my league. Hell I really don't even know what that is much less how to test it lol

 

[Sportster-2001-951C-Stock]

Now we r getting a little to technical. I am not a mechanic I know how to take stuff apart a put it back together but as far ad testing the RV cavity I think I might be out of my league. Hell I really don't even know what that is much less how to test it lol

Two hose nipples on crankcase(item 20 in this drawing attached link), one on either side of motor with hoses going back to oil tank, one to bottom of tank and one to top of tank. Empty oil tank (save oil in clean container, siphon oil out of tank through a piece tubing as necessary, keep this expensive oil clean and store it in a clean container so it doesn't get mixed with something else.) and disconnect these two oil lines from nipple (Item 20), drain out of lower one the oil in RV cavity and block one nipple, pressurize the other nipple to 5psi (bicycle pump and low pressure gauge 10psi top of scale range preferred are okay but need good valve to keep pressure from leaking back into bicycle pump) then seal and watch pressure to see if it leaks down over time, 10 minutes no leak is good, I think.

You also need a shop service manual for your ski, the entire teardown and buildup procedures are in there.

http://fiche.seadoowarehouse.com/se...asp?Type=18&make=seadoopwc&a=278&b=3&Action=O

 

[richey]

Two hose nipples on crankcase(item 20 in this drawing attached link), one on either side of motor with hoses going back to oil tank, one to bottom of tank and one to top of tank. Empty oil tank (save oil in clean container, siphon oil out of tank through a piece tubing as necessary, keep this expensive oil clean and store it in a clean container so it doesn't get mixed with something else.) and disconnect these two oil lines from nipple (Item 20), drain out of lower one the oil in RV cavity and block one nipple, pressurize the other nipple to 5psi (bicycle pump and low pressure gauge 10psi top of scale range preferred are okay but need good valve to keep pressure from leaking back into bicycle pump) then seal and watch pressure to see if it leaks down over time, 10 minutes no leak is good, I think.

You also need a shop service manual for your ski, the entire teardown and buildup procedures are in there.

http://fiche.seadoowarehouse.com/se...asp?Type=18&make=seadoopwc&a=278&b=3&Action=O

And the as for the lack of compression on the top end would that cause it not to get gas to the cylinders? I was able to get it to crank by spraying the carbs with gas but it would not stay running if i let off the throttle

 

[Sportster-2001-951C-Stock]

And the as for the lack of compression on the top end would that cause it not to get gas to the cylinders? I was able to get it to crank by spraying the carbs with gas but it would not stay running if i let off the throttle

Lack of compression can cause the fuel pump pulse signal to be low, so the fuel pump cannot pump fuel like it should, this may be the phenomenon you're witnessing.

You can maybe try an cheap(est) electric fuel pump to see if the no fuel symptom improves. Which carb is dry, is it the furthest one from the fuel pump? One carb has the fuel pump and the other doesn't, just one fuel pump mounted on side of one carb.

Pull fuel return hose coming from the carbs and see if fuel is returning to the fuel tank, this tells you probably enough fuel is being pumped by the fuel pump. If fuel pump pulse signal coming from the crankcase nipple is weak, the fuel pump performance can be insufficient.

 

[richey]

Lack of compression can cause the fuel pump pulse signal to be low, so the fuel pump cannot pump fuel like it should, this may be the phenomenon you're witnessing.

You can maybe try an cheap(est) electric fuel pump to see if the no fuel symptom improves. Which carb is dry, is it the furthest one from the fuel pump? One carb has the fuel pump and the other doesn't, just one fuel pump mounted on side of one carb.

Pull fuel return hose coming from the carbs and see if fuel is returning to the fuel tank, this tells you probably enough fuel is being pumped by the fuel pump. If fuel pump pulse signal coming from the crankcase nipple is weak, the fuel pump performance can be insufficient.

Well the more I read about it and the more we talk about I realize I have no idea what I am doing when it come to working on this thing. I think I have probably screwed it up more than I have fixed it because it was running just fine before the starter went out. I think I am going to just try to sell it for parts or something. U have any idea what it would be worth so I don't get screwed any further?

 

[Sportster-2001-951C-Stock]

Well the more I read about it and the more we talk about I realize I have no idea what I am doing when it come to working on this thing. I think I have probably screwed it up more than I have fixed it because it was running just fine before the starter went out. I think I am going to just try to sell it for parts or something. U have any idea what it would be worth so I don't get screwed any further?

I have no idea what you might get for it, a good rust free trailer is probably worth $150~$200, non-running but complete ski in good cosmetic shape maybe almost same? Then it goes by season too, maybe you find someone looking for a good winter project?

Craig's list? Drain the fuel and put it in your car if still decent.

 

[richey]

Lack of compression can cause the fuel pump pulse signal to be low, so the fuel pump cannot pump fuel like it should, this may be the phenomenon you're witnessing.

You can maybe try an cheap(est) electric fuel pump to see if the no fuel symptom improves. Which carb is dry, is it the furthest one from the fuel pump? One carb has the fuel pump and the other doesn't, just one fuel pump mounted on side of one carb.

Pull fuel return hose coming from the carbs and see if fuel is returning to the fuel tank, this tells you probably enough fuel is being pumped by the fuel pump. If fuel pump pulse signal coming from the crankcase nipple is weak, the fuel pump performance can be insufficient.

This ski doesn't have an electric fuel pump does it? I thought it operated off of vacuum.


I pulled the head last night and the cylinder walls and piston both look good. There was a little side to side play in the piston that I don't think should be there though and there was some build up on the top of the piston that when u rubbed it between ur fingers it felt course. Is that normal?

 

[Sportster-2001-951C-Stock]

This ski doesn't have an electric fuel pump does it? I thought it operated off of vacuum.


I pulled the head last night and the cylinder walls and piston both look good. There was a little side to side play in the piston that I don't think should be there though and there was some build up on the top of the piston that when u rubbed it between ur fingers it felt course. Is that normal?

If the existing mechanical fuel pump doesn't have enough signal to operate, an electric fuel pump amy be an option, that was my point.

That's good news, the cylinders are in good condition. The pistons will normally have some amount of carbon on the domes, and near the edges of the piston dome it should be bare aluminum ideally, about 1/4 to 1/2 inch aluminum exposed especially near the cylinder ports.

Too much piston heat causes fuel to burn too near piston surface, this, carbon builds on surface. Some carbon is normal. Fuel cools the piston, and heat is transferred from the piston to the cylinder walls by the close tolerance of the piston to cylinder and also heat leaves the piston through the piston rings, this keeps the fuel from burning at the piston surface and depositing carbon. Excessive carbon on the piston dome is a sign of piston overheating and promotes detonation, which will melt the aluminum piston. Lack of ring seal tends to increase piston temperature, because the rings transfer heat from the piston dome area into the cylinder wall through the oil film (the oil film can be destroyed by excessive heat and lack of oil causes extra heat due to no transfer of heat and more friction.).

So if your cylinder walls are unscored, then your pistons may still be in good condition. Especially if the clearance between the piston and cylinder appears to be close, still, which is important in order to transfer heat from the piston to the cylinder, through the oil film. If the clearance is too great, the piston will overheat.

So, it seems maybe you only need a new set of rings, a light hone (you can do this by hand, scrub cylinder well with hot hot water and dish sink soap to remove honing grit!) Maybe the original hone marks are gone by now.

The rings may overheated and collapsed, or they may have become stuck in the piston lands and no longer seal well with the cylinder. I have experienced this phenomenon before and simply removed the rings, cleaned the carbon from the piston lands, and reinstalled the original rings! This is often the case when working on antique outboard motors when parts are difficult to obtain.

Also, sometimes the rings are just stuck in congealed oil, in which case a solvent(such as automatic transmission fluid, which contains solvents) can loosen them. This happens by using cheap oil, and good oil keeps the ring lands clean by acting as a solvent to flush carbon deposits (decomposed hydrocarbons).

So it seems encouraging to me, I think the next step should be to remove the exhaust manifold and get a look at the piston sleeves, especially pay attention to the ring lands for carbon buildup, the rings may simply be stuck in the lands and needs disassembly for cleaning.

Or, you could try reinstalling the head and pour some automatic transmission fluid in the cylinders, crank the engine a bit to work it down in between the piston rings, and let it set for a week, then recheck compression to see if ring sealing has improved.

Nothing to loose, you'll at least need gaskets for reassembly.

Also, I think you should disassemble the carbs and make sure the small filters are clean, don't spray them with carb cleaner or they will melt, I would just use compressed air or rubbing alcohol, everyone says brake cleaner won't harm them. I always just replace them but that costs money. I would also clean the entire fuel system as best I could and replace any gray fuel lines with new ones from the autoparts store. First though, see if you can get the compression to increase before spending a lot of money.

How about removing the exhaust manifold to get a peek at the rings, and rock the crankshaft back and forth very slightly, just enough to see piston move, while watching to see if there's a slight amount of play(clearance) of the rings in the ring lands? If no slight play is perceptible, perhaps the rings are stuck in their lands and this explains ur low compression?

I like it. Let me know what you find?

 

[richey]

If the existing mechanical fuel pump doesn't have enough signal to operate, an electric fuel pump amy be an option, that was my point.

That's good news, the cylinders are in good condition. The pistons will normally have some amount of carbon on the domes, and near the edges of the piston dome it should be bare aluminum ideally, about 1/4 to 1/2 inch aluminum exposed especially near the cylinder ports.

Too much piston heat causes fuel to burn too near piston surface, this, carbon builds on surface. Some carbon is normal. Fuel cools the piston, and heat is transferred from the piston to the cylinder walls by the close tolerance of the piston to cylinder and also heat leaves the piston through the piston rings, this keeps the fuel from burning at the piston surface and depositing carbon. Excessive carbon on the piston dome is a sign of piston overheating and promotes detonation, which will melt the aluminum piston. Lack of ring seal tends to increase piston temperature, because the rings transfer heat from the piston dome area into the cylinder wall through the oil film (the oil film can be destroyed by excessive heat and lack of oil causes extra heat due to no transfer of heat and more friction.).

So if your cylinder walls are unscored, then your pistons may still be in good condition. Especially if the clearance between the piston and cylinder appears to be close, still, which is important in order to transfer heat from the piston to the cylinder, through the oil film. If the clearance is too great, the piston will overheat.

So, it seems maybe you only need a new set of rings, a light hone (you can do this by hand, scrub cylinder well with hot hot water and dish sink soap to remove honing grit!) Maybe the original hone marks are gone by now.

The rings may overheated and collapsed, or they may have become stuck in the piston lands and no longer seal well with the cylinder. I have experienced this phenomenon before and simply removed the rings, cleaned the carbon from the piston lands, and reinstalled the original rings! This is often the case when working on antique outboard motors when parts are difficult to obtain.

Also, sometimes the rings are just stuck in congealed oil, in which case a solvent(such as automatic transmission fluid, which contains solvents) can loosen them. This happens by using cheap oil, and good oil keeps the ring lands clean by acting as a solvent to flush carbon deposits (decomposed hydrocarbons).

So it seems encouraging to me, I think the next step should be to remove the exhaust manifold and get a look at the piston sleeves, especially pay attention to the ring lands for carbon buildup, the rings may simply be stuck in the lands and needs disassembly for cleaning.

Or, you could try reinstalling the head and pour some automatic transmission fluid in the cylinders, crank the engine a bit to work it down in between the piston rings, and let it set for a week, then recheck compression to see if ring sealing has improved.

Nothing to loose, you'll at least need gaskets for reassembly.

Also, I think you should disassemble the carbs and make sure the small filters are clean, don't spray them with carb cleaner or they will melt, I would just use compressed air or rubbing alcohol, everyone says brake cleaner won't harm them. I always just replace them but that costs money. I would also clean the entire fuel system as best I could and replace any gray fuel lines with new ones from the autoparts store. First though, see if you can get the compression to increase before spending a lot of money.

How about removing the exhaust manifold to get a peek at the rings, and rock the crankshaft back and forth very slightly, just enough to see piston move, while watching to see if there's a slight amount of play(clearance) of the rings in the ring lands? If no slight play is perceptible, perhaps the rings are stuck in their lands and this explains ur low compression?

I like it. Let me know what you find?

Ok I will do that. So a little side to side play in the list in is normal? Its not a lot of play but u can defiantly move the piston side to side

 

[Sportster-2001-951C-Stock]

Ok I will do that. So a little side to side play in the list in is normal? Its not a lot of play but u can defiantly move the piston side to side

Yes, you will be able to feel some wobble by pushing the piston crown around, the piston will heat up and the clearance will decrease as the piston expands from heat.

A look at the side of the piston and rings from through the exhaust port may tell more about the condition, I'm thinking the rings may simply be stuck in the ring lands. Sometimes if it's just a thick tarry goo, a solvent can dissolve and loosen them up. Good quality oil keeps this from happening. A solvent like automatic transmission fluid may loosen them enough to restore compression if this is what's happening, without any further disassembly.

It's up to you if you want to look at the side of the piston for more clues or try a solvent to unstick the rings but obviously you won't know the results until retesting the compression. I tend to think removing the exhaust manifold is the right move but in that case it's more work and will need gaskets, so it's your call on which plan of action to take. Unsticking rings by solvent may not work, you may have to remove the cylinders to access the rings and clean the grooves(ring lands). If so, try to find a ring installer tool, otherwise it's easy to break most types of rings by spreading them enough to remove. It can be done, and I've done it without a ring spreader/installer before, but you have to be careful.

Also the rings could already be broken from over revving, that would also cause low compression but it probably would scratch the cylinders if that happened.

Could also be the rings are just worn out as well, if I took the engine apart far enough to reach the rings, I would definitely try to replace the rings if I could. You will probably need to slide the new rings into the cylinder(a piston works good to push/position the ring and get the ring square in the cylinder) and measure the end gap using a gap gauge while the ring is in the cylinder, then remove and file the ring ends slightly to make the gap correct as necessary. So you need the correct size rings to start with, if the cylinders were bored at one time then there may be a specific size ring available.

Or, you could order a top end rebuild, send your cylinders to full bore and buy new pistons, they will measure bores and select the correct pistons then bore the cylinders to the correct dimensions.

But in this case(of spending money), you should pressure check the RV cavity to confirm the crankshaft seals aren't leaking, otherwise if they leak you'll need a remanufactured crankshaft.

So yes, it could get expensive depending on what you discover...... Think it through before ripping and tearing.