No, I cant. I received this thing in a bunch of boxe, so its been a bit of an adventure. I dont think the carbs had ever been messed with but when reassembling I didnt bother to check what exactly they were.
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1996 xp 800 first water test help!!
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No, I cant. I received this thing in a bunch of boxe, so its been a bit of an adventure. I dont think the carbs had ever been messed with but when reassembling I didnt bother to check what exactly they were.
ocod
Well-Known Member
So did Saber! Took it for granted after wasting a few rebuilds and new 2nd set of carbs
:facepalm:
It best to start fresh like you did resetting settings.
But opening LS that much something isn't right.
Sportster-2001-951C-Stock
Well-Known Member
Just b/c the carbs have never been messed with doesn't mean they're calibrated correctly, IMO.
Perhaps I should elaborate on the plug color I've witnessed, seems the slower I run my engine the more grey, or maybe I should really say black the plugs are, but in the test tank running at ~4500RPM, the plugs turn chocolate brown after just a couple of minutes.
I think plug color during low speed operation is really stretching this diagnostic mechanism, it's so dependent on the fuel and type of oil, I don't really look at my plugs often, I much prefer feeling the engine run and how it makes power while loaded, and how it sounds unloaded (unloaded rich four-stroking is good, that old 2-stroke ding, ding, ding), and how it responds to throttle changes in the water under load.
Perhaps I should elaborate on the plug color I've witnessed, seems the slower I run my engine the more grey, or maybe I should really say black the plugs are, but in the test tank running at ~4500RPM, the plugs turn chocolate brown after just a couple of minutes.
I think plug color during low speed operation is really stretching this diagnostic mechanism, it's so dependent on the fuel and type of oil, I don't really look at my plugs often, I much prefer feeling the engine run and how it makes power while loaded, and how it sounds unloaded (unloaded rich four-stroking is good, that old 2-stroke ding, ding, ding), and how it responds to throttle changes in the water under load.
Just tested by grounding and we are good there.... curious what temp the sensor is supposed to trip at???
What do you mean by 4 stroking??? I have heard that mentioned but am unfamiliar with the term.
So since most feel that I should verify jets etc can someone tell me what jets it should have. I have a couple rebuild kits coming from OSD and would like to get everything verified if im gonna pull these things apart.
I agree that I do need to verify, but I dont feel they are wrong. When I pulled the carbs apart they had a fair but not horrible amount of green gum in them from the old lines. So this tells me they were running at one time and for descent amount time. So if they ran that long I would figure the jets to be corrrect.... but who knows!!!
I agree that I do need to verify, but I dont feel they are wrong. When I pulled the carbs apart they had a fair but not horrible amount of green gum in them from the old lines. So this tells me they were running at one time and for descent amount time. So if they ran that long I would figure the jets to be corrrect.... but who knows!!!
ocod
Well-Known Member
| 1996 | xp | 787 | 270500284 | 270500285 | bn-40i (sb) | main-142.5 pilot-70 | 1.5 NEEDLE AND SEAT | 270500267 | 23 - 43 POP OFF | low- 1 high- 0 |
from
http://www.seadoosource.com/carbreference.html
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Sportster-2001-951C-Stock
Well-Known Member
The sensor must close above 94*C The test parameters and procedures are provided in most of the service manuals.
So I know this may be a stupid question... but I assume all the jets etc will have the size stamped on them.
ocod
Well-Known Member
Sportster-2001-951C-Stock
Well-Known Member
I can't tell you what exactly you must do to your boat or carbs to eliminate the lean condition you appear to be experiencing except tell you what my experience was on the 951 tune in my sportster, my mid-throttle lean bog was very pronounced IMO, and after thoroughly going through the entire fuel system several times confirming EVERYTHING was clean and working properly, I went up two sizes on my pilots and down one size on my metering spring with the expectation it would make the fuel mixture fatter, and it did. It's still this way, and arguably might be a hair too fat b/c it does four-stroke just a little coming off idle at no-wake speeds. It's at least not lean, 2-strokes should not be run too lean. This thing pulls like a mule now, I don't have to exercise the accelerator pump to nurse it along at all, anymore. Two-strokes need both fuel and oil, the fuel carries the oil throughout and cools the pistons, else they grind to an ugly death.
So I plan to leave mine this way until the next time the carbs come off, at which time I will go back to the original metering springs and MIGHT go down one pilot jet(already bought these ($10), from the original #75, to #77.5 It has an 80 gram spring and 80 pilot jet in it now and it runs and starts very well. I'm convinced the factory #75 pilot jet was just too lean for a nice clean mid range throttle response.
Yours sounds too lean in a similar way, so naturally my suggestion is to throw the next size jet in there and try it, it might fatten it up just enough to overcome your lean bog. BUT, only if you've already confirmed your carbs and fuel system are otherwise operating correctly and thoroughly clean, these things can't be half-plugged with goo, any small amount of goo in one of the "bypass holes" will give you a nice mid-throttle lean bog.
So, you might consider ordering a pair of 72.5 pilot jets and throwing them in there if by inspection you observe there is no trash in those three "bypass holes". I think this should eliminate the lean bog you're describing. ASSUMING EVERYTHING ELSE is working as it should.
Really, it's no big deal fattening up a two-stroke one jet size, considering they're on the hairy edge of being too lean on the factory calibration anyway.
So I plan to leave mine this way until the next time the carbs come off, at which time I will go back to the original metering springs and MIGHT go down one pilot jet(already bought these ($10), from the original #75, to #77.5 It has an 80 gram spring and 80 pilot jet in it now and it runs and starts very well. I'm convinced the factory #75 pilot jet was just too lean for a nice clean mid range throttle response.
Yours sounds too lean in a similar way, so naturally my suggestion is to throw the next size jet in there and try it, it might fatten it up just enough to overcome your lean bog. BUT, only if you've already confirmed your carbs and fuel system are otherwise operating correctly and thoroughly clean, these things can't be half-plugged with goo, any small amount of goo in one of the "bypass holes" will give you a nice mid-throttle lean bog.
So, you might consider ordering a pair of 72.5 pilot jets and throwing them in there if by inspection you observe there is no trash in those three "bypass holes". I think this should eliminate the lean bog you're describing. ASSUMING EVERYTHING ELSE is working as it should.
Really, it's no big deal fattening up a two-stroke one jet size, considering they're on the hairy edge of being too lean on the factory calibration anyway.
What do you mean when you say "4 stroke a little" ?
Sportster-2001-951C-Stock
Well-Known Member
4-stroking(rich miss) is the sound you listen for when tuning a 2-stroke carburetor. Basically, you want it just rich enough to 4-stroke occasionally, especially when it's not under load, it should 4 stroke, like when the impeller leaves the water, it should 4 stroke immediately. The goal is, no-load 4 stroking and then it cleans up when a load is placed on it. Since doing this(varying load) presents a challenge for us in a boat, the other approach is to fatten it up till it begins 4 stroking (missing from being too rich) then dial the mixture back slowly just until the 4 stroking stops. This point is sufficient fuel to get the engine in it's power band yet not run too lean where the pistons begin to overheat. A 2 stroke does make more power the leaner you run it, only to a kneepoint where there is no longer enough fuel to cool the piston, at which point the piston can expand beyond allowable tolerance and can lead to what's known as a lean seizure where aluminum can transfer from the piston to the cylinder wall and cause the rings to stick momentarily, in the molten aluminum deposits, or puddles. On occasion, a properly tuned two stroke might 4 stroke a bit, this is not abnormal, it's a sign the mixture is sufficiently rich, ie: not too lean. So, when tuning a 2 stroke carb, always start off rich (4 stroking) then dial the mixture back slowly until the 4 stroking just stops(under fully anticipated load vs throttle position), that's the sweet spot.
Sportster-2001-951C-Stock
Well-Known Member
Piston wash is probably a better mechanism to study than simply reading plugs, at least I think by watching the piston crown you can monitor the creep of carbon deposits toward the edge of the crown. Hopefully there's enough wash to keep the carbon growth from reaching the edge and down the side of the piston (a very lean condition). The fuel tends to "wash" the crown as it cools it, thus the overheated piston will have more carbon deposits covering the crown as the fuel burns closer to the surface of overheating pistons:
http://vintagesleds.com/bs/index.php?topic=65633.15
More on piston wash, this is better:
http://www.**************/forums/showthread.php?t=10089
http://vintagesleds.com/bs/index.php?topic=65633.15
More on piston wash, this is better:
http://www.**************/forums/showthread.php?t=10089
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Sportster-2001-951C-Stock
Well-Known Member
When you opened the idle mixture screws this far in order to get enough fuel to get mid throttle, did it have any negative effect on idle quality? Past 1/3 throttle, pop-off should not have much effect but at the low end around idle to about 1/3 throttle pop off can have a dramatic effect.
Basically, the idle mixture screws are intended for just adjusting for a smooth mixture at idle speed but if they're opened enough you can compensate at least partially for a lean mid-range mixture at the expense of a smooth idle and low end throttle response. I would say that if the idle mixture screw has to be opened much more than two turns to obtain sufficient fuel at idle, then the pop-off could be set too high. Too high of pop-off can also make for a hard starting condition. So, I would adjust the idle mixture screws for smoothest idle and if they end up more than 2 turns from open in order to obtain adequate fuel, then consider reducing pop-off pressure.
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The low speed needle didnt really have that much affect on the idle. Or at least that I can recall. I was more concerned with the miss and hesitation of the mid range.
I had a carb kit expressed from OSD and its scheduled to be here today. So I plan on pulling the carbs and replacing the popoff spring with the suggested spring (80 gram) I think. I will also check the jets etc to make sure they are the correct ones.
How do you feel is the best to check for the correct mix when tuning. I definitly dont want to run lean and would really like to keep it on the edge of fat just for safty sakes. Im having a hard time understanding the difference between a miss due to it being too rich or lean.
Sportster-2001-951C-Stock
Well-Known Member
"Im having a hard time understanding the difference between a miss due to it being too rich or lean."
Primarily the difference is, a lean miss often results in the engine stopping due to lack of fuel, at low speeds. 4 stroking is when the plug fires every 2nd compression stroke, so it usually wont stop running unless there's so much fuel it just can't fire. Adding more air(or less fuel), it cleans up after a few strokes as the excess crankcase fuel clears out. It runs, but the crankcase loads up. You should be able to achieve this at idle (or close to it) with your mixture screw by opening up this idle fuel orifice. Adjusting idle mixture with warm engine and impeller loaded, in water: Start, let's say, at one turn open and keep opening it you should feel the engine slow, which makes the engine also feel rough. At this point you're approaching the point where it will begin 4 stroking, it it's missing occasionally, those misses are called 4 stroking and you idle circuit is flowing adequately (because you have good control over idle mixture by adjusting the idle screw). Let's say from there you have to turn the idle mixture screws in very far to obtain a smooth idle and the engine still idles if you turn the screws in completely. In that case, the fuel is coming from the "bypass holes" and the idle screws have almost no, or little effect. The bypass holes should not be contributing fuel at idle, that's the job of the idle mixture port. If the bypass holes are volunteering fuel into the carb bore at idle and the idle mixture screw loses it's distinct effect to lean out the mixture enough to slow/stop the engine in a lean-out, the pop-off (arm or spring) probably should be increased.
But this idle circuit operation, if working properly, has almost no effect on throttle position greater than 1/3, where the bypass holes provide most of the fuel, the bypass holes provide a majority of the fuel from 1/3 all the way until the main venture begins to flow, which is about 70% of throttle position. Past 1/3 throttle, there is enough vacuum to pull the metering diaphragm fully against the metering needle arm and raise the metering needle fully off it's seat. Past 1/3 throttle, the metering spring/seat loses it effect, the metering spring/seat controls fuel at low speeds (assuming it's adjusted and functioning properly).
So, during mid range from 1/3 throttle to 70% throttle, the fuel is coming from the "bypass holes", and the pilot jet orifice size is in play.
If the mixture is too rich, you will hear 4 stroking that will clear with more air(by slowly opening the throttle) as the crankcase clears out and the engine will clean up with more throttle, it wont lean bog and die. A lean condition will not clear out like that, the engine will run out of fuel and lean-stop as the throttle is slowly opened. Jamming the throttle full open from there (say, 45% throttle can engage the main venturi if engine speed is high enough, and the engine catches and begins making power again.
It's the same thing as, turning up the fuel until the engine power decreases (it's nearly 4 stroking, or is 4 stroking), then turn it back until it clears out and power returns. Better to run a 2 stoke on the rich side as opposed to too lean but it will stop making power if it's too rich, then turn the mixture back from there just enough till the engine power comes back in(returns).
A 2 stroke engine that's missing due to being too rich, has oil in the cylinder (the fuel carries it there), a 2 stroke that's missing due to being too lean has no oil in the cylinder (there's no fuel carrying it there). An excessively rich engine will lose power (because it only fires every other stroke) but not lean-stop, because it's still firing(every other compression stroke), where as an engine running too lean will stop, due to lack of fuel.
So, I think your idle mixture circuit is working properly if you can lean-stop the engine by turning in the idle mixture screws. In that case, I wouldn't decrease the pop-off unless you can't get enough fuel through the idle circuit to 4 stroke by opening the idle screws not more than a couple of turns. If you must open the idle mixture screws more than 2 turns to obtatin enough fuel for a smooth or slightly rich idle, the the pop off could be too high.
Final adjustment should all be done with the air box arrestor installed, of course, and this all assumes your carbs are in good condition internally, no gum clogging the ports or something like that.
The old round pump Mikuni's used to have a third screw on it, to allow external adjustment of mid range mixture, now with the super BN you have to change the pilot jet. This is probably because since a majority of the fuel during part throttle running (who rides WOT all the time?) comes from the "bypass holes", thus a fixed jet suffices the EPA's fear you might be able to adjust your 2 stoke engine properly.
WHEWWWW thats a read... great info sir... im gonna go at it again tonight and see what we have.
thanks
Sportster-2001-951C-Stock
Well-Known Member
Here's a video of a guy adjusting a 2 stroke engine to 4 stroke as it should when it has no load, indicating the engine has a sufficient amount of fuel and is almost too rich but notice as he tunes the engine the 4 stroking cleans up when a load is placed on the engine the engine pulls well and makes good power, it doesn't lean out and die as a load is placed on it:
http://www.youtube.com/v/5BZkB9QQTJU&hl=en&fs=1
And his description of what he's doing and observing:
"There's more to tuning than just adjusting the high end, but this is a start. It also gives an excellent example of what 4-stroking sounds like.
In the first cut, the engine continues to 4-stroke, even towards the bottom of the cut. That's a little too rich. It should run clean all the way through the cut once under load.
After that first cut, I tune the High Speed screw. I turn the H screw in clockwise until the engine peaks out and is totally 2-stroking. No 4-stroke at all. I then quickly richen the mixture back up by turning the H needle counter-clockwise. Immediately you hear the engine begine 4-stroking again.
The next cut you can hear the engine immediately clean out once underload, and stay that way for the entire cut. After that cut I rev the engine and you can hear that it is still 4-stroking at WOT. It's important to check for that after a cut, since that's when your engine will be its hottest and leanest(after running WOT under full load for some period).
http://www.youtube.com/v/5BZkB9QQTJU&hl=en&fs=1
And his description of what he's doing and observing:
"There's more to tuning than just adjusting the high end, but this is a start. It also gives an excellent example of what 4-stroking sounds like.
In the first cut, the engine continues to 4-stroke, even towards the bottom of the cut. That's a little too rich. It should run clean all the way through the cut once under load.
After that first cut, I tune the High Speed screw. I turn the H screw in clockwise until the engine peaks out and is totally 2-stroking. No 4-stroke at all. I then quickly richen the mixture back up by turning the H needle counter-clockwise. Immediately you hear the engine begine 4-stroking again.
The next cut you can hear the engine immediately clean out once underload, and stay that way for the entire cut. After that cut I rev the engine and you can hear that it is still 4-stroking at WOT. It's important to check for that after a cut, since that's when your engine will be its hottest and leanest(after running WOT under full load for some period).
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thanks a bunch for this.... I am not able to view at the moment but this should really help me get a better feel for whats going on.
Water Horse IV
New Member
No boundaries Sports in Mount Washington, KY. The owner's name is Kevin. This is not the shop where my1996 GTI is (ready for pick up/ jury's out until I launch @ Nolin Lake). However, after a long thorough search, this guy came highly recommended. The number is (502) 215-4859.
Okay another update... Rebuilt the carbs with a kit from OSD. Found o rings around the jets to be coming apart so im sure they were not sealing. Also replaced the popoff spring with a new 80 gram which was suggested as being correct. All jets etc were verified to be the correct size. All holes etc were once again cleaned and verfied to be free of any debries.
So im gonn set them to factory specs and try again.
So im gonn set them to factory specs and try again.
ocod
Well-Known Member
And the winner is you and your ski!
Keeping fingers crossed that she runs like a bat out of hell!
Okay, we are finally getting there. Finally got old yeller out on the water for a good test and it ran much better. Was still bogging when the throttle was mashed but that was eliminated when I slightly opened up the low needles.
My only 3 real complaints are (1) that from 0 - 1/2 (roughly) throttle, I seem to have a miss. It just doesnt seem to run as consistant or smooth as it does when I hit the half way point. From 1/2 to full it runs like a champ. (2) It also idles what I consider pretty rough. (3) I have to pump the throttle a little when starting to get it running. Choking it does nothing. (Yes the choke works).
Any thoughts on what could be wrong.
Started the day set with carbs that were just rebuilt. Specs set to factory, and a new 80 gram pop off spring installed.
Ended with the lows set to roughly 1.25 open, and highs were never adjusted.
My only 3 real complaints are (1) that from 0 - 1/2 (roughly) throttle, I seem to have a miss. It just doesnt seem to run as consistant or smooth as it does when I hit the half way point. From 1/2 to full it runs like a champ. (2) It also idles what I consider pretty rough. (3) I have to pump the throttle a little when starting to get it running. Choking it does nothing. (Yes the choke works).
Any thoughts on what could be wrong.
Started the day set with carbs that were just rebuilt. Specs set to factory, and a new 80 gram pop off spring installed.
Ended with the lows set to roughly 1.25 open, and highs were never adjusted.
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ocod
Well-Known Member
I would say its all normal for a 787. It's hard to describe how a two stroke sounds at different rpms.
They do not like the no wake 1/4 throttle paces. Its either half to full throttle to be in the power band of the engine.
If you open the low it will bog the acceleration worse at lower throttle speeds.
Do you have a tach? In the water rpm is ~1500. if you don't, just close it a little if its running high. It will sound like it has a miss at idle.
http://www.youtube.com/watch?v=3zoNDhhJW0o
Not sure on the last one other than choking it may be giving it too much gas while pumping throttle is just enough???
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