Sorry about that Trevor, got to reading and didn't realize you were the OP. I deleted my comment.
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Help: 2001 Seadoo GTX
- Thread starter TrevorM
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As etemplet said yours takes the 2.0 needle and seat Mikuni # 786-35018-2.0. THe 35018 are the newest but hard to find and the 35015 is perfectly fine, you can also search for #14-1077 and Amazon has the same 786-35015-2.0 for $17.00.
The carb kits are #MK-BN46I. Also keep in mind your carbs use a special spring that are specific to that carb only.
The carb kits are #MK-BN46I. Also keep in mind your carbs use a special spring that are specific to that carb only.
TrevorM
Active Member
Thank you kind sirs! I have purchased genuine Mikuni carb kits. I also purchased the needle and seats, however after looking at the part# I think they might be aftermarket... may give them a try they have a 60 day return so worse comes to worse I'll return them! Should be getting my new WSM fuel selector tomorrow so the seadoo should be finished next week!
If the needle and seats dont have a square stamped next to the 2.0 size on the bottom they are not genuine Mikuni and should be avoided at all cost. IF you run them there is a very good chance they will cause problems and you will be doing it all over again.
This is the square you are looking for but obviously this is not a seat, just and example.
This is the square you are looking for but obviously this is not a seat, just and example.
Sportster-2001-951C-Stock
Well-Known Member
IMO, you should replace the metering needle b/c the rubber tip will have a small wear groove that hangs up in the brass seat orifice after many years of being pressed against the seat and the lubricant impregnated in the viton rubber tip will be washed away over time as well. Look for an ethanol proof needle but I think they all are, nowadays? The N/S set should come with a new o-ring for installing the seat or your kit will have the o-ring and that o-ring should be replaced with new at the same time so it's trouble-free (no leaks around the o-ring). Lubricant might help install the seat, I slather or bath everything, including screws, in 2-stroke oil or ATF.
Often aftermarket parts spell trouble and you need to look for/expect that. For instance the metering seat orifice might have a minuscule burr from the drilling process and this causes the rubber needle tip to stick/hang in the seat. Feel free to polish the inside of the seat using a q-tip and a dab of lapping compound then clean it out good of course, this makes them operate smoother and less sticky. It's not mandatory if there's no burr and the seat is well machined.
Anyway, I obtained my n/s from bayareapowresports Yorktown Va and I noticed even though the bag had a new sticker it was on top of the OEM Mikuni sticker. Well. I figured they were Mikuni and they worked fine but I checked them out VERY carefully.
Inspect all aftermarket parts VERY closely and with great skepticism (Dial Caliper and/or micrometer are a start) b/c small differences that you cannot detect CAN make a huge difference.
On the fuel line, try heating the marine line with a hair dryer or heat gun if you have one, which will soften it but don't overheat it (heat guns get mighty hot). IMO, it's perfectly acceptable to use automotive fuel line and I guess you'll wind up doing this if you cannot get that impossible to work with heavy wall marine stuff to work (It's a real challenge and arguably not with the time).
Often aftermarket parts spell trouble and you need to look for/expect that. For instance the metering seat orifice might have a minuscule burr from the drilling process and this causes the rubber needle tip to stick/hang in the seat. Feel free to polish the inside of the seat using a q-tip and a dab of lapping compound then clean it out good of course, this makes them operate smoother and less sticky. It's not mandatory if there's no burr and the seat is well machined.
Anyway, I obtained my n/s from bayareapowresports Yorktown Va and I noticed even though the bag had a new sticker it was on top of the OEM Mikuni sticker. Well. I figured they were Mikuni and they worked fine but I checked them out VERY carefully.
Inspect all aftermarket parts VERY closely and with great skepticism (Dial Caliper and/or micrometer are a start) b/c small differences that you cannot detect CAN make a huge difference.
On the fuel line, try heating the marine line with a hair dryer or heat gun if you have one, which will soften it but don't overheat it (heat guns get mighty hot). IMO, it's perfectly acceptable to use automotive fuel line and I guess you'll wind up doing this if you cannot get that impossible to work with heavy wall marine stuff to work (It's a real challenge and arguably not with the time).
Sportster-2001-951C-Stock
Well-Known Member
Reuse the original metering springs unless they're damaged, since you have no way of measuring spring strength and often replacements are not made as well as the originals (even Mikuni has stuff outsourced to China?)
FWIW, I wanted to fatten up my carbs a bit just off-idle and provide a little earlier startup fuel without making idle richer so I installed 65gr springs in place of the original 80gr springs. If you look at Mikuni's chart this doesn't drop pop by a large amount. I made some other changes to make it richer in part throttle as well but honestly, I don't believe lowering the pop with the lighter spring made much difference if any (surely some difference though) and looking at Mikuni's chart kinda explains why.
15 minute heat soak hot start is perfect.
For the record, I don't condone changing a factory tune willy-nilly.
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Sportster-2001-951C-Stock
Well-Known Member
Trevor, I recall you asked about alternative fuel line clamps and I forgot to mention many outboards also use the herbie type nylon plastic clamps. Determining the right size Depends on the final OD of your tubing, perhaps the C size herbie clamps would be handy (measure 1st, of course)?
Hose Clamp - Herbie Clip Nylon Size C - Black - Hose Clamps
Hose Clamp - Herbie Clip Nylon Size C - Black - Hose Clamps
TrevorM
Active Member
This is exactly where I bought my needle and seat. I am sure they are aftermarket though. On eBay they listed the brand as "747" whatever that means. The reason I bought them was because bayareapowersports is where I bought the genuine Mikuni rebuild kits, so I just assumed the n/s were genuine as well... Well I don't know what I should do now. Use the originals, use the already bought N/S, or go hunt down Geniune Mikuni N/S....
Also I got the fuels lines to work by using a heat gun works wonders. Bad news on the fuels selector. I got my new one in and guess what it's the wrong one! I can't seem to find a new fuel selector for the 947/951 Seadoo GTX... every single one I've came across says universal use "except 947/951" so I'm returning the fuel selector and continuing the hunt.
Also tomorrow I will be trying to pull the carbs off so wish me luck.
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I do business with Bay Area as well they are my goto supplier. You have to specify that you want genuine Mikuni Needles and seats. They are about $18 each. That's all I use on carbs and even that package looks like aftermarket but they are not. I called... LOL The performance says they are genuine also. There is so much aftermarket stuff in the market place that t it is difficult to get the good stuff, even when you pay extra for it. I also purchase genuine mikuni springs. That takes out a whole lot of the spring swapping and extra pop off testing out of the picture. Generally it is install test and I'm done.
TrevorM
Active Member
These needle and seat came in a two pack for $30, so I'm going to just guess by the price that they aren't genuine Mikuni. I may just return them. I wanted to get the seadoo ready for Labor Day weekend so I don't know what I'm going to do now... I might see how the original needle and seat look and may try to reuse as the seadoo runs amazing I just wanted to get rid of the tempfuel lines and clean the carbs just in case that junk go into them.
Also I haven't gotten to look at the needle and seats physically as they just got ordered/delivered and I work a lot, so I will check the stampings tonight.
UPDATE
Got the carbs off after one bolt nut and an allen socket went MIA in the hull (still missing)! Anyways pulled the carbs out and found this random small in diameter black hose that wasn't connected to anything... the hose is long in length and tried to see where it goes. More investigation will be required. Also when the carbs came out I noticed only one of the butterfly holes had a big o-ring on it and the other didnt! I'm bad at describing stuff and I'm not sure how to post pictures on here but in the service manual under the fuel system/intake diagram (pg. 310 on pdf) I am referring to no. 11 & 12.
Also the needle and seat read "757 International" part number is that of WSM #006-361. So I will be returning these as they are most definitely aftermarket.
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Sportster-2001-951C-Stock
Well-Known Member
I think if you want to return the n/s for genuine that's not a bad choice, OEM is always a safe bet but I'm confident you should able to detect differences in n/s by careful inspection. You should use a caliper gauge to confirm the dimensions (esp overall length of assembly) and be careful not to damage (nick, gouge, crush or smash) the rubber tip of the metering needle.
The two aftermarket parts that seem to be inferior quality are the small mylar reed check valve mounted on the metering plate (I normally skip replacing this reed unless it's bent away from the through-hole or otherwise physically damaged in some way) and the fuel metering diaphragm which should be near as soft as a rose petal and held up to a light, you should not see holes.
I normally don't remove and replace the fuel pump circular reeds either, unless they're obviously damaged (occasionally they may be cracked or bent).
I use a magnet on a stick for fishing around or compressed air gun to blow stuff from the bilge, you can tip the bow upward sometimes and cause stuff to roll out from under the motor.
The two aftermarket parts that seem to be inferior quality are the small mylar reed check valve mounted on the metering plate (I normally skip replacing this reed unless it's bent away from the through-hole or otherwise physically damaged in some way) and the fuel metering diaphragm which should be near as soft as a rose petal and held up to a light, you should not see holes.
I normally don't remove and replace the fuel pump circular reeds either, unless they're obviously damaged (occasionally they may be cracked or bent).
I use a magnet on a stick for fishing around or compressed air gun to blow stuff from the bilge, you can tip the bow upward sometimes and cause stuff to roll out from under the motor.
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TrevorM
Active Member
I will be returning these n/s as I found genuine for about the same price! I feel more comfortable with genuine as well especially since I already bought the genuine rebuild kits.
Also I will be replacing everything that is describe in Miki's carb rebuild tutorial as that is what I'm trying to follow.
Any idea on the big o-ring and the hose I found disconnected? The hose looks like a long version of those tiny black vacuum hoses on the carbs.
UPDATE
So I was searching these forums and guess what I found?! Another user with the exact seadoo model who found the same black line as me! Need help with oil line. Looks like it's the battery vent tube!
This place is great so much useful info!
Also I will be replacing everything that is describe in Miki's carb rebuild tutorial as that is what I'm trying to follow.
Any idea on the big o-ring and the hose I found disconnected? The hose looks like a long version of those tiny black vacuum hoses on the carbs.
UPDATE
So I was searching these forums and guess what I found?! Another user with the exact seadoo model who found the same black line as me! Need help with oil line. Looks like it's the battery vent tube!
This place is great so much useful info!
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Sportster-2001-951C-Stock
Well-Known Member
I was gonna say. sounds like the lead/acid wet electrolyte vent tube. This tube goes to a small overboard thru-hull fitting to avoid corrosive acid spills in the bilge.
TrevorM
Active Member
So I am positive that this battery I have in the seadoo is sealed as it is a brand new battery from previous owner. What would be recommended to do with the unconnected vent hose? Also the big huge o ring #11/12 on diagram does that need to be on both butterfly ports of the carbs? Mine only has the one. It looks like the diagram depicts only one.
Also my genuine Mikuni N/S come in tomorrow or Thursday so I should be getting everything back up to running shortly!
Also my genuine Mikuni N/S come in tomorrow or Thursday so I should be getting everything back up to running shortly!
TrevorM
Active Member
Funny you mentioned WSM #006-604 I've ordered this exact one yesterday hoping to have it by Friday. Also thanks for the response I will need to find a place to get the big o-ring because my carbs came off with only one as shown similarly in the diagram!
Also this might be a really stupid question but when the carbs were taken off there seems to have only been two physical cables the throttle and the choke isn't there suppose to an oil pump injection cable?
Again thanks a ton! Everyone has been a tremendous help!
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Sportster-2001-951C-Stock
Well-Known Member
Search inside the plastic flame arrestor airbox or bilge for the missing o-ring. You CAN run without it but might notice some vibration and this isn't something I'd do if I could help it (that's just me, I gotta have it right, LOL). This o-ring makes the seal with the flame arrestor so without both, it's not the way it left from the factory. Perhaps you can find a prplacement at the local hardware or autoparts store, possibly Harbor freight includes this size in one of their kits?
Sportster-2001-951C-Stock
Well-Known Member
Yep, AFAIK all the 951's had the dual cable. On mine (2001 boat), the ignition advance switch was defective and the oil inner wire was frayed a little so I replaced the back half which includes the splitter.
TrevorM
Active Member
Thanks to all of you once again! So I'm a little bummed out as my Mikuni needle and seat were suppose to be guranteed delivery yesterday, but now won't be here until tomorrow... Anyways I have found the oem airbox to carb o ring and have ordered and should be here tomorrow with the n/s. I am going to get this project done by this weekend.
I am a little worried about hooking everything back up such as the throttle and choke cables. I know it was mentioned the throttle and oil pump were integrated but I'm not sure what this means as far as requiring adjustments. As far as adjustments go all I need to do is make sure both carbs open and closes at the same time correct? No oil cable adjustments? I never touched the back lock nuts on the cables I just unscrewed the cable nuts to remove them from the carbs to hopefully save the adjustments from before.
Also with the base gaskets I bought brand new oem ones do I need to put any type of gasket sealer on them as well or just use the gaskets without anything else?
Thanks again everyone you have no idea how much this place has helped me through my project!
I am a little worried about hooking everything back up such as the throttle and choke cables. I know it was mentioned the throttle and oil pump were integrated but I'm not sure what this means as far as requiring adjustments. As far as adjustments go all I need to do is make sure both carbs open and closes at the same time correct? No oil cable adjustments? I never touched the back lock nuts on the cables I just unscrewed the cable nuts to remove them from the carbs to hopefully save the adjustments from before.
Also with the base gaskets I bought brand new oem ones do I need to put any type of gasket sealer on them as well or just use the gaskets without anything else?
Thanks again everyone you have no idea how much this place has helped me through my project!
For the cables you should set the throttle cable so you have about 2mm of play at the handlebar lever. Then adjust the oil pump so that the two lines are aligned.
The gaskets go on dry from the factory but I like to use a super thin coat of ThreeBond 1211.
The gaskets go on dry from the factory but I like to use a super thin coat of ThreeBond 1211.
TrevorM
Active Member
Update
first off let me start off by saying I'm a little disappointed. I have all fuels lines replaced, brand new fuel selector, brand new spark plugs, and carbs rebuilt.
The reason I'm a little disappointing is because taking off the gray tempo fuel lines I found no "green goo" I also rebuilt both carbs and found zero "green goo" inside. In fact the filters look new! I even tested the pop off of the old needle and seat and they were good. Previous owner said nothing was ever rebuilt. He always had it serviced at a seadoo dealer and that's it.
I feel stupid as my father once said "don't fix something that's not broken." Anyways once everything was put back together it took awhile to start the seadoo. I started getting super worried. Eventually the seadoo fired up. We started it up a few times to ensure everything was running smoothly. We even hooked up a hose and flushed it.
We do have one concern and that is with the RPM. This thing runs like crazy on the trailer with a high RPM! The RPMS continued to climb and hit over 3000 and I pulled the lanyard as I was afraid it was going too high. We also did throttle it and I saw the RPMS hit in the 9000. We didn't mess with any settings on the carbs such as the low and high speed screws. The pop off for both carbs were around ~23psi. I will say after the initial tough time starting up the seadoo fires up at a touch of a button.
Honestly guys I am worried that I have done more harm than good and I wish I could go back and not touch the carbs. I will be taking the seadoo out tomorrow to see how things go on the water so wish me luck!
first off let me start off by saying I'm a little disappointed. I have all fuels lines replaced, brand new fuel selector, brand new spark plugs, and carbs rebuilt.
The reason I'm a little disappointing is because taking off the gray tempo fuel lines I found no "green goo" I also rebuilt both carbs and found zero "green goo" inside. In fact the filters look new! I even tested the pop off of the old needle and seat and they were good. Previous owner said nothing was ever rebuilt. He always had it serviced at a seadoo dealer and that's it.
I feel stupid as my father once said "don't fix something that's not broken." Anyways once everything was put back together it took awhile to start the seadoo. I started getting super worried. Eventually the seadoo fired up. We started it up a few times to ensure everything was running smoothly. We even hooked up a hose and flushed it.
We do have one concern and that is with the RPM. This thing runs like crazy on the trailer with a high RPM! The RPMS continued to climb and hit over 3000 and I pulled the lanyard as I was afraid it was going too high. We also did throttle it and I saw the RPMS hit in the 9000. We didn't mess with any settings on the carbs such as the low and high speed screws. The pop off for both carbs were around ~23psi. I will say after the initial tough time starting up the seadoo fires up at a touch of a button.
Honestly guys I am worried that I have done more harm than good and I wish I could go back and not touch the carbs. I will be taking the seadoo out tomorrow to see how things go on the water so wish me luck!
You did the right thing as 99.9% of them need the carbs and fuel system rebuilt. Think of it this way, you spent $150 on parts not needed instead of a $1,000 engine if it did need it.
For the runaway, it is very common on the 951 engine since they are so lean due to EPA regulations. I make it a point not to rev mine out of the water because of this. Even a perfect 951 can runaway in the trailer. If it does it again just pull the choke and it will flood it out. It’s the safest way to kill a runaway.
For the runaway, it is very common on the 951 engine since they are so lean due to EPA regulations. I make it a point not to rev mine out of the water because of this. Even a perfect 951 can runaway in the trailer. If it does it again just pull the choke and it will flood it out. It’s the safest way to kill a runaway.
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