Hi guys, I put new Mikuni Carb kits in my 1994 GTX and after reinstalling them it's flooding out heavily. Upon first attempted startup it ran for maybe 15 seconds but it was rough. It continued to foul plugs after that and when I say foul I mean soaked in fuel. I messed with it so long that my battery died so I charged the battery overnight. In the morning I reinstalled the battery, took the plugs out and turned the engine over a few times to get any excess gas out. A lot of gas came out I mean like a couple cups of gas blew out of the heads. Is that my needle not seated right? Note that I did not replace the needles. One of them had a little bit of a ring wore into it very slight and the other one looked okay. I did not test pop off as I don't have the tool for it. Also I never really messed with the jets I just blew them out with carb cleaner and made sure they were clear. I did however take the low idle adjuster out and put a new seal on it on both carbs put it back in and then backed them out one and a quarter turn. I bought this ski off a guy that had already replaced all the fuel lines. It was stalling out at higher speeds so after reading a bunch of forums I thought it might be the smallfuel filters in the carbs.turns out he must have replaced the easy carb but the one that's hard to get to the one I had actually removed was 3/4 clogged up. So I replaced both filters, gaskets, diaphragms, the clear round plastic discs, seals on needles but that's it, used old needles, springs, levers.
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Pop off adjustment
- Thread starter Jgreelz
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Hi guys, I put new Mikuni Carb kits in my 1994 GTX and after reinstalling them it's flooding out heavily. Upon first attempted startup it ran for maybe 15 seconds but it was rough. It continued to foul plugs after that and when I say foul I mean soaked in fuel. I messed with it so long that my battery died so I charged the battery overnight. In the morning I reinstalled the battery, took the plugs out and turned the engine over a few times to get any excess gas out. A lot of gas came out I mean like a couple cups of gas blew out of the heads. Is that my needle not seated right? Note that I did not replace the needles. One of them had a little bit of a ring wore into it very slight and the other one looked okay. I did not test pop off as I don't have the tool for it. Also I never really messed with the jets I just blew them out with carb cleaner and made sure they were clear. I did however take the low idle adjuster out and put a new seal on it on both carbs put it back in and then backed them out one and a quarter turn. I bought this ski off a guy that had already replaced all the fuel lines. It was stalling out at higher speeds so after reading a bunch of forums I thought it might be the smallfuel filters in the carbs.turns out he must have replaced the easy carb but the one that's hard to get to the one I had actually removed was 3/4 clogged up. So I replaced both filters, gaskets, diaphragms, the clear round plastic discs, seals on needles but that's it, used old needles, springs, levers.
AKnarrowback
Well-Known Member
1 - Did you use real Mikuni carb kits or aftermarket kits?
2 - You need to be able to test the pop off pressure to do a good rebuild on the carbs. If the needle and seat has any sign of wear they need to be replaced.
2 - You need to be able to test the pop off pressure to do a good rebuild on the carbs. If the needle and seat has any sign of wear they need to be replaced.
How can I tell the difference between real and aftermarket? I got them off eBay they were labeled mikuni carb kits but maybe they're not real I'm going to order a new needles and seats What's the best place to order them from? Also something I noticed there was a difference between the needles in each carb, one went through the little lever right in the middle there's a tiny hole in it. The other needle on the other carb it went around the lever across the whole top of it. Is that normal?
And as far as the carb kit diaphragm goes, it seemed like a nice diaphragm. Much better than the ones that were in there. The little lip around the edge of the diaphragm that goes into the carb ring to seal was thicker and sturdier than the old ones. I don't know if that tells you it's an actual mikuni car rebuild kit or not but that's about the only difference I noticed.
AKnarrowback
Well-Known Member
A thicker material isn't better since the pump relys on a flexing action to move the gas. I'd say you do not have original mikuni parts in there.
Go to OSD Marine, order the original mikuni carb rebuild kits and new mikuni needle and seats.
Go to OSD Marine, order the original mikuni carb rebuild kits and new mikuni needle and seats.
GGuillot
Well-Known Member
Totally related to it flooding, you should replace the needle/seats with an genuine oem set and ck the pop off psi.
Ok I think that's my first plan as of now is to find new needles and seats. First question do they to be OEM or can they be genuine mikuni? Second question do I need seats as well? Third question I've read that the seat can be lubricated to install easier and not damage rubber seal, what should I use as a lubricant?
GGuillot
Well-Known Member
Cost diff is minuscule for aftermarket vs. OEM. The aftermarkets usually have a cheaper rubber material on the tips that don't hold up like a viton rubber tip would. Needles and seats are purchased as one.. slight dab of lithium grease on the oring will help the seat settling in good when you install them.
Don't overlook the detail of at least checking the pop off psi afterward, as this will confirm if it's holding and 'popping' in spec.
Ok I was definitely going to get needles with viton tips, looks like mikuni needles do have Viton. Just having trouble finding a set of 2.0 size at the moment. OSD marine carries them but they are out of stock. Thanks for the lithium grease response and yes I need to purchase a pop off tester/pump as well. Spec say 22 to 29 psi from what I found.
Looks like I found Genuine Mikuni Diaphragms and needles/seats for $80 shipped. I also found OEM parts but it's $165. Will I be all set with Mikuni? Also you got a recommendation for a pop off tester purchase?
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In the beginning,,,I fabricated a big bicycle pump with a guage on it, to test the needle in the seat, and popoff,,,then later,,,when I got into racing, of course I needed the mikuni pump...
The seat doesn't really wear,,,the rubber tip wears...my guess, is that your needle is sticking,,,,what is easy to overlook, Is for for scoring on the sides of the needle,,,happened to me once,,,filled my crankcase with gas,,,had no petcock,,,
Use a strong magnifying glass,,,and I bet you a Covid 19 vaccine,,,you have scoring on the 4 corners of the needle,,,and that the needle tip is pretty good.
The seat doesn't really wear,,,the rubber tip wears...my guess, is that your needle is sticking,,,,what is easy to overlook, Is for for scoring on the sides of the needle,,,happened to me once,,,filled my crankcase with gas,,,had no petcock,,,
Use a strong magnifying glass,,,and I bet you a Covid 19 vaccine,,,you have scoring on the 4 corners of the needle,,,and that the needle tip is pretty good.
AKnarrowback
Well-Known Member
Get a tester, it is as important as a screwdriver or wrench when it comes to making your machine run right.
We have a mix up in communication. The diaphragm you are talking about is for the regulator action on the carb, I was refering to the fuel pump diaphragm.
What color is the metal button in the center of the diaphragm you currently have in the carbs?
We have a mix up in communication. The diaphragm you are talking about is for the regulator action on the carb, I was refering to the fuel pump diaphragm.
What color is the metal button in the center of the diaphragm you currently have in the carbs?
A Covid 19 vaccine lmao.
I'm about to buy a new set of needles and diaphragms. I looked at the tips and on one of them I could see a slight ring around it so maybe it's not seating right. However it ran a lot better before the carb rebuild and I didn't replace the needles, so I'm wondering if it's the aftermarket mikuni diaphragms I installed. I'm buying a mikuni pop off tester too so this time I will know their good before i reinstall them.
Yup I'm ordering a genuine mikuni tester, needles and diaphragms right now.
If it ran better before the servicing,,,then,,,perhaps you have made an error somewhere in your installation,,,the new parts should not make the carbs run worse.
Okay,,,the new parts shouldn't make it run poorly immediately,,,did you pressure the needle and seat,,,did you pressure test the carb as a unit for leaks,,,do you have both base gaskets in place?
Okay,,,the new parts shouldn't make it run poorly immediately,,,did you pressure the needle and seat,,,did you pressure test the carb as a unit for leaks,,,do you have both base gaskets in place?
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That's my thinking but I can't see where I did anything wrong watched a couple videos beforehand to make sure I had a good idea of what I was doing. All gaskets/seals seamed to fit we'll. All I can figure is those aftermarket diaphragms are junk or the new seals on the needle seats aren't sealing properly. The one little card fuel filter was 3/4 clogged so it should run better. The other thought is that now that the filters are clear it should be getting more gas flow and maybe those old needles are wore out too much for the better gas flow but I really am just guessing.
Also had this question guys. Each carb has a fuel line coming from the tank or pump in the tank. There's also a fuel line between the carbs connecting them. The lines are clear. The first line from the tank to the first carb is filled with gas. The line connecting the carbs is also filled with gas. The line on the second carb going to the tank is clear, there's no gas in it. Is that normal, is it just a return or overflow line back to the tank or does it feed that second carb? Should it also be filled with gas?
GGuillot
Well-Known Member
I'm not here to promote any one vendor, but I've bought complete kits from bayarea through ebay twice. Genuine kits, w needle/seats and base gaskets. This about what I paid shipped.....price is almost the same, maybe a few dollars from a couple years ago. Sea Doo Dual Genuine Mikuni Carb Rebuild Kit Base Gasket & Needle Seat GTX 92-94 | eBay
Also had this question guys. Each carb has a fuel line coming from the tank or pump in the tank. There's also a fuel line between the carbs connecting them. The lines are clear. The first line from the tank to the first carb is filled with gas. The line connecting the carbs is also filled with gas. The line on the second carb going to the tank is clear, there's no gas in it. Is that normal, is it just a return or overflow line back to the tank or does it feed that second carb? Should it also be filled with gas?
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