1995 seadoo sp. I can't figure out this bog.

[TurnerBFC]

Guys, I'll keep this short.

95 sp. Replaced all fuel lines, rebuilt carb with mikuni kit. Replaced pressure valve. Replaced check valve in vent line. New plugs. Trimmed plug wires back.

Starts and idles great. I go full throttle from idle and it takes a good few seconds to clear its throat. Then sometimes on plane, I go full throttle and it bogs down.

I can't lose this bog. Any ideas ?

 

[Coastiejoe]

Did you clean or replace the fuel selector?


Sent from my iPhone using Tapatalk

 

[TurnerBFC]

I cleaned it very well

 

[mashenden]

Same ski, same things done, and pretty much the same problem here too. Carb rebuilt with OEM, new selector switch, new lines, new plugs, fresh non-ethanol gas, fresh oil.

Last weekend it ran better than it ever has - a slight problem starting if I even touched the gas, but otherwise it fired up and ran fine all weekend. This weekend it starts, gets up on a plane fast, and goes about 100' and then loses power... Presumably what you refer to as a bog. I don't know where to start. I've read several posts on carb cleaning and adjustments but it is starting to blurr.

Hopefully someone with good carb knowledge can set us in the right direction.

 

[Dr Honda]

Sounds like.....


1) Pop-off is too high. (When you open the throttle quick, the Vac drops, and you cut the fuel)

2) The bypass ports are clogged.

3) Compression is low. (If the engine is getting tired, it's hard to tune)


Personally... I'd just pull the carbs again, and take a look.

 

[drewski]

Mine was doing the same thing. I cleaned the fuel selector, confirmed its operating. Turned out to be the fuel selector after all, learned that after i bypassed it it worked perfect. Check youre gas vents, o-ring on fuel filter and try by-passing the selector. Good luck.

 

[TurnerBFC]

Sounds like.....


1) Pop-off is too high. (When you open the throttle quick, the Vac drops, and you cut the fuel)

2) The bypass ports are clogged.

3) Compression is low. (If the engine is getting tired, it's hard to tune)


Personally... I'd just pull the carbs again, and take a look.

Ok. I know a bit about these machines, but the bypass ports are new to me. What are those exactly?

I'm going to switch fuel valves with one I know works 100% and try it.

 

[Prime Target]

Try changing out he fuel selector switch. I had a similar problem with my GSX last year after doing the carbs and fuel lines. It was a dirty selector switch for me. The selector switches are tough to clean. They are cheap and easy to replace.

 

[mashenden]

Turner BFC, your symptoms sound VERY similar to mine. Be sure to read my thread. http://www.seadooforum.com/showthread.php?77708-Carb-Confusion

For mine, I think Dr Honda was on the right track with the "compression is low - tired engine" theory. While mine was a new rebuild like yours, I suspect my oil injection was not working right and as I tried to fix what I thought was a carb in need of adjustment (everything else was new and/or rebuilt including the fuel selector switch), it was a quickly deteriorating engine due to a lack of oil as I weened it off the "rebuild break-in oil in gas" process.

Its too late for me, but if I were you I'd do a compression test to see if things are going down hill, and if so, add oil to your gas before doing any more testing or maybe pull the carb and make 100% sure the oil injectors are working.

 

[Dr Honda]

The bypass ports are the small openings in the "Low Speed" circuit in the carb. When one or more are plugged... you don't flow enough fuel in the transition.


One other thing comes to mind... The low speed check valve could be leaking. When that happens, you suck all the fuel out of the regulator section, so when you open the throttle... there's simply no fuel to give.



So basically... I'd say to open the carbs, and check them out.

 

[mashenden]

Dr Honda - I am nowhere near the level of the real experts on this forum, but given what happened to mine, I wonder if you have any thoughts on my theory?

 

[TurnerBFC]

The bypass ports are the small openings in the "Low Speed" circuit in the carb. When one or more are plugged... you don't flow enough fuel in the transition.


One other thing comes to mind... The low speed check valve could be leaking. When that happens, you suck all the fuel out of the regulator section, so when you open the throttle... there's simply no fuel to give.



So basically... I'd say to open the carbs, and check them out.

Fair enough. I will do a compression test and open the carb again and do a pop-off test and do a look-around in the carbs.

 

[TurnerBFC]

The bypass ports are the small openings in the "Low Speed" circuit in the carb. When one or more are plugged... you don't flow enough fuel in the transition.


One other thing comes to mind... The low speed check valve could be leaking. When that happens, you suck all the fuel out of the regulator section, so when you open the throttle... there's simply no fuel to give.



So basically... I'd say to open the carbs, and check them out.

Also, when I did the check valves. I had a very hard time determining the "curve" they haver and which side the blue ink mark was on. I am not sure if I installed them correctly or not. Any tips how to check this visually when I remove the carb again?

 

[mikidymac]

To see what side has the ink stripe on the check valves, use a small dab of brake cleaner on a rag and try the wipe it. If it comes off that is the correct side. The side with the ink should face up.

 

[TurnerBFC]

To see what side has the ink stripe on the check valves, use a small dab of brake cleaner on a rag and try the wipe it. If it comes off that is the correct side. The side with the ink should face up.

Sounds good!

 

[mashenden]

But in case there is confusion, I am pretty sure the check valve that Dr Honda mentioned in the low speed circuit is not the round ones, but is the tear drop shaped one that is attached with a screw to the removable metal block. This one did not have an ink mark on mine.

 

[Dr Honda]

Also, when I did the check valves. I had a very hard time determining the "curve" they haver and which side the blue ink mark was on. I am not sure if I installed them correctly or not. Any tips how to check this visually when I remove the carb again?

OK... that's the wrong valves. The big round valves are the pump valves. The one I'm talking about is the small, oval shaped valve that is on the back side of the regulator block. (The cover over the high speed jet) It needs to be perfectly flat to seal. Also, if that block has corrosion... the valve may not seal.

 

[TurnerBFC]

OK... that's the wrong valves. The big round valves are the pump valves. The one I'm talking about is the small, oval shaped valve that is on the back side of the regulator block. (The cover over the high speed jet) It needs to be perfectly flat to seal. Also, if that block has corrosion... the valve may not seal.

I tried to replace that but wow...that screw would not budge. It "looked" like it was sitting flat and sealing but I ended up leaving it.

 

[Dr Honda]

Could be the prob.


If it's flat, and not warn... then it SHOULD be ok. But they get hard, and warp, and stop sealing.

 

[TurnerBFC]

Could be the prob.


If it's flat, and not warn... then it SHOULD be ok. But they get hard, and warp, and stop sealing.

So this weekend whilst at the cottage, I took the carb out and removed all components. I sprayed out every port with brake cleaner and checked that all was well visually. I did not have an air compressor.

Compression was 145 psi on both cylinders. I replaced the inline fuel filter and put it all back together. I noticed the little oval shaped valve was actually slightly lifted and I don't think it was seating correctly, I had to put it back together as I did not have a replacement.

So once I took it out, it was perfect for about 25 minutes, then it all went to crap again. I go full throttle from a stand still and it will take me 15 seconds...seriously, to get on plane and then it starts to open up. Plugs are nice tan/brown colour.

I don't know what is going on with this machine. Could it be this little oval-shaped check valve?

Thanks