Looking for some help. Carb issues?

[RyanB72]

Hi All, I am having some continued issues with my 2000 GTI ski not running right.

To give you some background, a friend rebuilt the carb and fixed the issue with the fuel sending unit. In the process of this he got a few fuel lines mixed up and an odd problem here and there with the carb. I've pulled the carb apart and fixed the fuel line problems (ON and RETURN were switched). Verified both Jet's are clear of obstructions, I've blown all passages out with air and carb cleaner. Verified that the 3 tiny holes are all clear going from the low speed circuit to the throttle body. Verified that the arm for the needle is flush like the manual states it should be. Carb was put back together, high speed screw all the way in, low speed screw was 1 1/2 turn out.

I went through the shop manual and performed most of the tests for the carb. My pop off pressure is near 40psi. I say near as I am using a pressure regulator on my air tank. It's close. Using stock silver spring. The fuel pump hold pressure and vacuum where it needs to. I've cranked the engine and held my finger over the return outlet and verified it has fuel pressure.

OK, on to the problem. The ski starts up without issues. Idles just fine in and out of the water when you start it. Out of the water it rev's very well. When I get it in the water and get past 1/4 throttle it just doesn't do anything. RPM's stay about the same. Then when I get to 3/4 throttle it takes off. If I back off the throttle it wants to die and many times it does if I try to let is idle after coming off full acceleration. After about 5-10 minutes though it loses power even at full throttle.

The high speed screw was all the way in. I noticed the plugs seem to look like it's running lean. I turned the high speed screw out a half turn. Made no difference at high speed. Plugs still look lean.

So after about an hour of messing with it on the water I pulled it out and came home. I am hoping I can get some second of direction what to do before taking it back out to the water.

Thanks any one for any assistance you can provide.

~Ryan

 

[donkey]

maybe suckin air in the pickup baffle,or the water seperator oring,i had an issue with that,to verify,i used (tempoary)clear fuel line,rode without the seat,verified bubbles in fuel line,found a crack in the baffle line,close to the top.worth a shot.
troy

 

[manolocross]

Did your friend change the gray fuel lines if there were any??? The lines would say TEMPO on them.

 

[RebuiltSeadooBaffles]

Did you check the internal carb filter? (you didnt mention it so just putting that out there). Have you ran compression numbers on the engine? Get a fram inline (clear) fuel filter to verify that the carb(s) are getting fuel with the engine running.

 

[RyanB72]

Hi, thanks for the replies. Fuel lines were replaced. Carb was completely gone through again. I verified the filter was 100% clean.

I can put a clear fuel filter on it. This should verify the "air in the lines" possibility. I know it's getting fuel as the engine is running. Just not very well as described.

EDIT: I have not run compression test yet. I'll do that tonight.

 

[bell99man]

It sounds like something is still in the midrange circuit maybe. Also, did you replace the carb base gasket. Are the bolts tight. If you can't track it down, Dr Honda has a wonderful carb rebuild service.

 

[manolocross]

Check The pulse line from engine block to carb fuel pump. Make sure the clamps are tight and the hose itself is in good shape.

 

[RyanB72]

OK. I checked the compression. I don't have the adapter to run the water so I can warm it up so I did this cold. It's hard to stop it at 3 stroke so I am getting 4. 120psi on stroke 3 and 130 PSI on stroke 4. Same for both Cyl.

I double-checked with a mirror and made sure that the carb base gasket is properly in place. It is also a new gasket.

I verified just using my finger on the pulse line. I pulled it off, hit the starter and could feel the pulse. All fitting are tight on the pulse line.

I know it's getting gas, as mentioned when I 1st put it into the water I'll get maybe 5-10 minutes at wide open before I lose power there. There is no power from 1/4 throttle to 3/4 throttle at all times. I don't yet have the clear fuel filter to check for flow and bubbles. Need to go buy that.

Is there a link to Dr Honda's website or something? Or should I just PM him? I've read his carb post that is stickied many times but I didn't see any info about his rebuild service.

Any further questions or things to try please let me know. Thanks for the assistance.

~RyanB

 

[bell99man]

Just click on his name on one of these threads and PM him. That is basically how he sets it up. He'll give you a price based on what you send and most of the turn around time is shipping unless he is swamped with other work, but he will let you know that, too.

When doing a compression test pull both plugs and put the wires on the lugs near the battery. hit the start button and hold the throttle wide open. this is for best air flow. with the other plug out you will get less resistance on the starter. Just turn it over until the needle on the gauge stops rising and that is your compression. It may take 5-15 sec to peak out. 130 is low for that motor but recheck it and you can warm it up dry. Just run it for 15-30 sec to warm the contact parts up. It won't hurt for that little bit.

Wait, your ski has a female hose fitting in the rear above the pump. Get a $5 hose valve from a garden store. They usually have a female end that spins for attaching the hose. Here is one from Home Depot:
http://www.homedepot.com/p/t/100659...&productId=100659291&R=100659291#.UZrf-6LIGAQ


Put it on the ski and then use that to connect the hose. Start it first and then turn on the water. water off and then slowly go turn off the ski.

 

[bell99man]

This is how good the Doc is:
http://www.seadooforum.com/showthread.php?61545-rust-found-in-carb

 

[RyanB72]

Hmmm. That is interesting on the 'crank it for 10-15 seconds'. I've always been told to warm up the motor and get 3 good compressions. Course this is on 4 stroke motors. I did have both plugs out. I'll warm it up a bit as soon as I can and post back.

Thanks for the help.

 

[RyanB72]

OK. Warmed it up. Pull the plugs and after about 8 seconds of cranking it's not going up any further on each cyl. Maxes out at 140psi. It is a 2000 GTI with I think the 717? Is that low? What is normal?

 

[kicker]

Normal is in the 150 range. Now it should run still at 140 and it is good that you are getting a reading that is the same on both cylinder.

Did you clean or replace the fuel selector switch and check the O ring in the bottom?

 

[RyanB72]

I only blew through it with carb cleaner and air. I did not take it apart, and didn't do anything with an O ring. I'll look into that today.

 

[RyanB72]

OK. I pulled the fuel selector apart. The O ring looks fine. No leaks there. No obstructions, I put carb cleaner and air through each opening.

I put a clear fuel filter on the intake line. It fills about 1/2 full of fuel. Still air in it. I do not see any air bubbles being added to it. I got the adapter and was able to run water through the ski while running it as well. So I ran it for a good 5 minutes. Revving it pretty good. I haven't noticed any problems with all the checks you guys have asked about so far. The ski seems as normal as it has been. It always reved ok out of the water.

Any other suggestions? thanks!

 

[bell99man]

PM this guy and ask him to read this thread. He knows that carb like few others do.

http://www.seadooforum.com/member.php?16022-Dr-Honda

 

[kicker]

Was a pop off test done when the carbs were rebuilt or cleaned?

 

[RyanB72]

Hi, yes I did the pop off test after going back through the carb myself. It is very near 40 PSI. Hard to tell as I had to use a pressure regulator on my compressor to test it.

I am hesitant to PM Dr Honda directly as there is a post in the sticky about not doing so.

 

[Dr Honda]

Hi, yes I did the pop off test after going back through the carb myself. It is very near 40 PSI. Hard to tell as I had to use a pressure regulator on my compressor to test it.

I am hesitant to PM Dr Honda directly as there is a post in the sticky about not doing so.

You did the right thing. You made a post... tried to get some help... and then asked me to look it over. Let me get a little more coffee into me, and I'll read it over.

 

[Dr Honda]

I'm at a little of a loss.... it sounds like you've checked everything


No power change from 1/4 to 3/4 throttle would tell me that you aren't getting fuel from your high jet. Also... power falling off, and suspect of running lean would be the same.


So... the carb needs to come back off, and check:

1) The high speed check valve, on the back of the jet block. It needs to sit perfectly flat.

2) the O-ring on the high speed screw. (between the spring, and the carb body) If it's hard, and not sealing... then you can suck air.


Along with that... you have an accelerator pump. Make sure it's working. If it's not... then you will get the same issues. (no progress until fully into the high speed section of the carb)



Then... double check the pop-off. Make sure you have a little oil in the needle and seat, so you get a clean "pop". I use shop air too... and it's not any harder to tell with air, or a hand pump. BUT... what you need to do is... put 10 psi on it... and listen for leaks. Then, turn it up, until you get a clean pop. If it just starts to hiss... stop, let the pressure out... and put a few more drops of oil down into the needle.

40 PSI is your high side... I would target the lower side. Also... the arm being flush is just a starting point. You can bend it up to 1mm to adjust the pop-off.


And finally... you said that you have "The stock silver spring". BUT... is it the FACTORY spring, or the one from the rebuild kit? If it's from the rebuild kit... and it was an aftermarket kit... the spring could be the prob. Put in the OLD FACTORY spring, and call it a day. Unless you use OEM Mikuni springs... they don't work right.

 

[RyanB72]

Thanks Dr Honda. It doesnt really give me a pop. It starts to hiss at 40 psi. I've put DW40 down it. The kit apparently did not come with a new needle and seat. I am going to pick up whats left of the kit and old stuff from my friend and go through it. I saw a post about the clear plastic part of the after market kits not being up to spec either so was thinking of putting the old one back in. He wasnt sure of they replaced the spring or not but said there was an 'old' spring that looked a bit rusty in the remnants of the kit so they much have replaced it. Though they also did the carb in his ski so it may be from his as well. I'll try going to that spring and re-test the pop off.

Do you sell needles/seat's?

 

[RyanB72]

Been super busy so took me a bit to come back to this. I got the old kit back from my friend and found the original spring. Put that in and now my "pop" off pressure seems to be about 30psi. however it's still not a pop. It's a hiss and spit WD40 at 30psi. I've ordered a needle/seat and waiting for it to come. May take the ski out this weekend as it is now to see if the 30psi pop off works better than the 40psi?

 

[RyanB72]

Well today I was excited because I got the needle/seat earlier than expected. I ran out and put it in the carb and now I am confused. The old Needle/seat is a 2.0. After reading the carb thread it suggested I stick with the 1.5 so that Is what I ordered. While running this test after putting in the old spring on the 2.0 needle/seat I got the needle 'leaking' at about 30 psi. I dont get a "pop".

After putting in the new genuine mikuni needle/seat I bought that is a 1.5, my "pop" off was like 55. And I STILL don't get a pop. It starts 'leaking' at 55. I then gently bent the bar so it is 1-2 mm above flush and it came down to 45... I don't know what I am doing wrong. Please see below youtube of my test with the new needle/seat. I am very hesitant to run it this way. It would be better to have the 30 "pop" off with the larger needle/seat wouldn't it?


http://www.youtube.com/watch?v=Zdue1eq10gY

 

[Dr Honda]

You should get a clean "pop." Don't use WD40. It's mostly kerosene, and it's hard on the rubber parts. Use a light oil... like 3n1. Put a few drops around the needle, and then tap the arm to make sure the tip is wet.


Now... Who said you need a 1.5 N/S? If you have a single 40mm carb... then it uses the 2.0. The 1.5's were used in the twin carb 800's, 951's, and some 720's.

 

[RyanB72]

You should get a clean "pop." Don't use WD40. It's mostly kerosene, and it's hard on the rubber parts. Use a light oil... like 3n1. Put a few drops around the needle, and then tap the arm to make sure the tip is wet.


Now... Who said you need a 1.5 N/S? If you have a single 40mm carb... then it uses the 2.0. The 1.5's were used in the twin carb 800's, 951's, and some 720's.

Hi and Thanks for the response Dr Honda. I actually got both of them from the Carb Adjustments thread at the top of the forum. If I am anything, it is a meticulous reader.

From the follow statement I made (the wrong?) assumption that we should just got 1.5 needle size for everything.

Note: It is recommended that you do not use too large a needle valve for your
application. Many tuners recommend using 2.3 or 2.5 needle valve in all cases. Actually, we recommend using the smallest needle valve that gives you the correct pop-off pressure for your engine. A 1.5 needle valve can flow the maximum amount of fuel that the Super BN can pump, so the only reason to use a larger needle valve is to obtain the correct needle valve and arm spring combination (pop-off) for your watercraft.

Also from the Carb Adjustment thread about WD40:

4. During testing, it is important to obtain consistent readings. To accomplish
this, it is necessary to keep the needle valve wet. Use WD-40 or something
similar to wet the needle valve.

After reading your reply that I should still be at 2.0 needle and seat and not to use WD40 as I read previously, I put the 2.0 seat back in. However I took out the needle from the 1.5 measured it and it's identical to the 2.0. I swapped that in. I don't have 3in1 oil, so I just dabbed 2cycle oil onto my finger and generously dabbed it onto the needle until it soaked down and whatnot.

I finally have a "pop". And it's at the more desirable 30 psi. I should be taking the ski out this Sunday for a test run. My Confidence is back up that I may finally have things resolved. I'll report back how things went.

You may want to update the thread to not use WD40 and maybe make it more clear that the 'smallest size' isn't really the recommended one. I really appreciate everyone's help and your patience with me.

~RyanB