951 bogs but will hit top speed

[Racerhoze]

1999 GTX Limited. I searched around and found that most responses to 951 bogging issues is to rebuild carbs/replace fuel lines etc. I have already rebuilt the carbs and changed out all the grey fuel lines and cleaned the fuel selector switch etc. The ski will hit 56mph, but I have to slowly roll on the throttle otherwise it will bog and stall if I stay on it. I suspect the accelerator pump. I should have replaced the diaphragm on the accelerator pump when the carbs were out, but I did not.

Background... the ski sat for 10 years before coming into my possession. Only has 51 hours on it.

Thoughts?

 

[pwgsx]

The Acc. Pump for sure but the diaphragm might be ok. Check the nozzles that squirt into the carbs: I bet they are clogged. Check the small lines as well but dont replace them. Also make sure the arm is pressing down on the shaft of the pump too.

 

[Racerhoze]

The Acc. Pump for sure but the diaphragm might be ok. Check the nozzles that squirt into the carbs: I bet they are clogged. Check the small lines as well but dont replace them. Also make sure the arm is pressing down on the shaft of the pump too.

Do these diaphragms generally not need replacing? I sprayed the crap out of the nozzles with carb cleaner when rebuilding. Is there a way to flush these lines out without pulling the carbs again?

 

[JJinSC]

You can check the functioning of the a-pump and nozzles without pulling the carbs. However, you will need a mirror and will have to pull the air box off. Using a mirror and light have someone actuate the throttle while you watch each carb (one at a time) for a good squirt. Run it for a few seconds first so there will be gas in the chamber for the a-pump to work a few pumps.

If no squirts then pull the appropriate small line off of the nipple and blast cleaner through the nipple/nozzle. To make sure a-pump diaphragm is working. Do the same test above with one if the small lines lose to make sure it is pumping to the nozzles.

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[Racerhoze]

Good to know! Will be tough to get at the small lines though. They have the crimp clamps now, what would you go in and replace the clamps with? I don't know if the typical worm gear clamps go that small!

 

[Dr Honda]

Do these diaphragms generally not need replacing? I sprayed the crap out of the nozzles with carb cleaner when rebuilding. Is there a way to flush these lines out without pulling the carbs again?

Well.... here's where the issue probably is.

"Spraying the crap out of the nozzles" isn't cleaning the nozzles. Did you verify 100% that they were clear, and the cleaner could pass the entire system? (past the nozzle, past the check-valves, and so on)


No... there is ABSOLUTLY NO WAY to clean/check the carbs without removal, and COMPLETE disassembly.


Before I closed my shop, I can't tell you how many times I heard... "I cleaned the carbs x times, but it still wont run." THEN... I would pull them apart, and dang near every passage was plugged with crap.

 

[JJinSC]

Small zip ties. I used small dremel cutting wheel to remove the oetiker clamps


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[Racerhoze]

Well.... here's where the issue probably is.

"Spraying the crap out of the nozzles" isn't cleaning the nozzles. Did you verify 100% that they were clear, and the cleaner could pass the entire system? (past the nozzle, past the check-valves, and so on)


No... there is ABSOLUTLY NO WAY to clean/check the carbs without removal, and COMPLETE disassembly.


Before I closed my shop, I can't tell you how many times I heard... "I cleaned the carbs x times, but it still wont run." THEN... I would pull them apart, and dang near every passage was plugged with crap.

I did completely disassemble the carbs, but not the accelerator pump. Honestly this is my first time messing with anything carb'd that is bigger than a push mower. So it is my mistake not cleaning out the accelerator pump lines and jets.

 

[pwgsx]

Check the larger of the small grey lines. It feeds the pump and might be clogged.

 

[SabrToothSqrl]

The Accelerator pump only activates when punching it off the line... if you're already doing 5,000 RPM and want to jump to 7k, it's not doing anything.

My guess is something is blocking the fuel flow.

Also, more important the MPH is the RPM. what's the max RPM you see, in the water?

 

[clmboating]

The Accelerator pump only activates when punching it off the line... if you're already doing 5,000 RPM and want to jump to 7k, it's not doing anything.

My guess is something is blocking the fuel flow.

Also, more important the MPH is the RPM. what's the max RPM you see, in the water?

So on an 96' GTX it'll do the same?

 

[SabrToothSqrl]

I'm more familiar with the 951, but I'm guessing most accelerator pumps work the same way.

They push fuel because when you have low RPM combined with opening a big hole (opening the throttle), the air isn't moving fast enough to draw sufficient fuel.

 

[Racerhoze]

The Accelerator pump only activates when punching it off the line... if you're already doing 5,000 RPM and want to jump to 7k, it's not doing anything.

My guess is something is blocking the fuel flow.

Also, more important the MPH is the RPM. what's the max RPM you see, in the water?

It really isn't jumping from 5-7K, more like 3100 to 7K where it bogs.

Max RPM was about 65xx or 67xx (I think?)

 

[JJinSC]

Well.... here's where the issue probably is.

"Spraying the crap out of the nozzles" isn't cleaning the nozzles. Did you verify 100% that they were clear, and the cleaner could pass the entire system? (past the nozzle, past the check-valves, and so on)


No... there is ABSOLUTLY NO WAY to clean/check the carbs without removal, and COMPLETE disassembly.


Before I closed my shop, I can't tell you how many times I heard... "I cleaned the carbs x times, but it still wont run." THEN... I would pull them apart, and dang near every passage was plugged with crap.

Doc, he was speaking solely of the a-pump circuit here. It's functionality can absolutely be checked without pulling the carbs. However, if an issue is discovered that turns out not to be in the a-pump lines or nozzles, then at the very least he will have to pull the PTO carb.

Interesting thought though that spraying the a-pump nozzles is not cleaning them. I am not questioning you, but I may need to learn something here too. How else can you properly clean the a-pump nozzles.


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[SabrToothSqrl]

Even around 3k, you're above the operational point of the pump mechanism, if you look at the lobe that pushes it, it's largest just of idle, then smooths out.

I suspect an issue with fuel delivery. I don't know where, but it sounds as if not enough fuel is going in.

So, lines, selector, carbs, and or even the fuel pump could be worn out... it is 15 years old...

I've personally had more luck with buying new carbs around $400, and selling the old for $150-200 than in rebuilding them, as brand new means brand new lots of parts, and you know they are 'good'.

 

[Racerhoze]

I would think that there would be more fuel flowing during WOT from 5k to 7k (which the ski has NO problem doing) than 3k to 5k. I could be wrong though.

 

[Esmalls]

Im having the same issue on y 98 GSX Ltd.
Def going to check the A-Pump.
My RPMs are right around 6900 on smooth water.

 

[gman1103]

I've personally had more luck with buying new carbs around $400, and selling the old for $150-200 than in rebuilding them, as brand new means brand new lots of parts, and you know they are 'good'.

Where would you recommend buying a new carb. and are there any reputable companies or fellow forum members who rebuild carbs?

 

[SabrToothSqrl]

I buy from OSDParts. If you want used Minnetonka will hook you up.

 

[paperman]

Well.... here's where the issue probably is.

"Spraying the crap out of the nozzles" isn't cleaning the nozzles. Did you verify 100% that they were clear, and the cleaner could pass the entire system? (past the nozzle, past the check-valves, and so on)


No... there is ABSOLUTLY NO WAY to clean/check the carbs without removal, and COMPLETE disassembly.


Before I closed my shop, I can't tell you how many times I heard... "I cleaned the carbs x times, but it still wont run." THEN... I would pull them apart, and dang near every passage was plugged with crap.

so I am one of those people that have said " I have cleaned and rebuilt the carbs"
how do I clean the passages?
my 98 gtx still does not run right after my carb rebuild.

 

[Esmalls]

Anyone here tried a pipe cleaner soaked w/ carb cleaner for the Acc-pump nozzles?

 

[1of500]

Just blast them with carb cleaner until they are clear

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[mikidymac]

On my 2001 XP that had been sitting for 5+ years the carb cleaner would not clear the a-pump nozzles. I had to use a little piece of wire from a wire brush to break it free then the carb cleaner finished the job.

 

[Esmalls]

Cleaned my A-pump last night on my GSX L. Wasn't too bad. Nozzles into carb were blocked up tight,..nothing spraying into carb.
Removed air box Pulled hoses off pump and tested the pump. Hoses squirted gas when removed from a-pump, but wasn't reaching carbs.
(Used make-up mirror to look onto carbs while pulling throttle)
Used a pipe cleaner with some carb cleaner on it to go in as far as I could. Then sprayed carb cleaner directly into pump nozzle with the little straw. (careful of back spray.....YUCK )
Then put blow nozzle from air compressor on it and blew it out.
Took a few tries, but eventually did the trick. Water testing this weekend.

Also,..whoever had it before me had the low speed screws backed out over 2 turns. Brought them back in to 1 1/4.

 

[drjack]

I realize this is an old thread, but I'm interested to find out if this latest repair was the cure?