1997 gtx proper idle rpm

[trabich]

Hey all, I just did a complete top end rebuild on my 97 gtx 787. After hooking it up to the garden hose it likes to idle around 4,000 rpm. Is this norma out of the water? What should the idle rpm's be? I reset the carbs to what I was told the factory settings were ( high needle = 1 turn out and 1/2 turn on low pto carb and 0 on mag)

I did spray wd-40 around carb gaskets and got no increase in rpm's so I think I'm good there.

 

[jhjesse]

Hey trabich,
See you finally got her going. That's great. I think your settings should be 3000 out of the water and 1500 in the water. :cheers:

 

[trabich]

hey jhjesse, Yeah man it's been fun getting this thing in top shape again. I just hope everything is good with it. I haven't gotten a chance to get it in the water yet. I will get the tegs for it this week. The idle just seemed pretty high even for being out of the water. I checked the linkage and sprayed wd-40 around the carb gaskets. everything looked good there. Of course when I pulled the choke linkage the idle came down for a second then went back up to 4k. Do you think it's just an idle adjustment?

 

[jhjesse]

Yeah just bring her down a little on the idle adjustment, but make sure at the final idle setting your two lines on the oil pump are aligned...if not, just make a oil pump linkage adjustment. You should be good to go.

 

[trabich]

you know I had a guy tell me to check the line to be sure that they are lined up. It was the tech at our local sea doo dealer. He showed me a new lever and what lines to line up. I looked with a telescopic mirror and couldn't see the line on the moving half. Can I easily take that lever off to see what I'm dealing with. When I adjust the idle stop screw is it going to throw those lines off.

Also, Am I supposed to gap the plugs?

 

[kustomkarl]

The correct carb settings should be Lowspeed Screw 1 1/2 turns out. the High Speed Screw should be set to "0". The spark plug gap should be set at.021-.024" and use NGK BR8ES spark plugs. The engine should idle at 3000rpm's on the trailer and 1500 rpm's in the water under load. Once the carbs are in sync, check the oil pump to be sure the lines align, you don't need to take off the cable disk to see the marks. Look closely and you should see them. Once the carbs and oil pump cables are set they should be in sync too, so with a little throttle the oil pump cable moves at the exact time. Be sure they are in sync. Then when you adjust the idle the carbs and oil pump will always be in sync at any idle adjustment you make. There is 1 screw that adjusts the idle of both carbs at the same time. Do not use the LOW SPEED SCREWS to adjust the idle. Before you start it up check to see that the cable for the carbs is allowing the carb to go to full open and snap to full closed for idle position.

Karl

 

[jhjesse]

Couldn't have said it better Karl!!:cheers:

 

[trabich]

hey carl & jesse, is the high speed adj to be set at 0 on both carbs?


You know I tackled a complete rebuild on this 97 gtx. Everything from top end to fuel lines to new seats and even allnew electronics. I could not have done any of this with out you guys. I appreciate it! After this rebuild I really wouldn't mind working for sea doo.

 

[jhjesse]

Trabich'
Thanks, I really like helping people out.

I just looked on the 1997GTX specification sheet Mikuni BN401 carbs.
The low is 1 turn with a plus or minus of 1/4 turn. The high on the Mag carb is 0, and the high on the PTO carb is 1/2 turn.

Hope this helps. :cheers:

 

[trabich]

now that is what I have them set at now. The high needle is the one on the bottom that is T shaped right? And the low speed needle is on the top side with a flat head screw adjuster. Am I correct? When he said 1 1/2 turns out I was starting to think that was my problem. But everyone else was saying 1/2 turn. So we are still looking at adjusting the idle stop screw huh?

 

[jhjesse]

Trabich,
Go to the upper right hand corner of this web page and click on parts.
Go to the part that says "By Year" and click on it. Then click on 1997 and then click on GTX. Scroll down to where it says carburetor and click on it.
When the diagram comes up enlarge it and look at these numbers.
#33 - Low setting screw
#48 - High setting screw
#59 - Idle setting screw. Remember that you only have one idle screw for both carbs.

Hope this answers your questions.

 

[trabich]

I just took carbs back off. Looking at the idle stop screw I backed it off about a 1/4 of a turn. After I got to looking at it it looked like the lever wasn't even hitting the stop screw. If I leave the air box and filter off for tunning will it run right?

 

[trabich]

Jesse you are awesome. I pulled the carbs off again last night and wnt over all needles again. now the parts break down had the idle adj screw labeled wrong. after figuring everything out and doing a complete reset we are good to go. Sarted it up as soon as I got home today and she idled right at 3,000 rpms. This baby is ready to fly. with the bored out cylinders and oversized pistons this thing should really fly! THANK YOU SO MUCH!

 

[jhjesse]

Good to hear that you got your ski running good.
About the "awesome" part...don't tell anyone it might get out.:lols: