Another 951 problem

[richie0270]

I have a '09 GTX LTD 951. Fuel lines are fresh and I have fitted an external rectifier kit from Seadoosource.
The Ski starts instantly, compression is good and it runs really well, for about a mile...

Then it starts to bog down below 4000 rmp, it feels like it is struggling to get going.
Pumping the throttle makes no difference, but as soon as I open up the throttle fully it struggles to reach 4500, but then past that is runs really cleanly and goes like stink.

As soon as I back off the throttle is starts to bog down again and struggles to get going again. But then again it gets to above 4500 rmp and runs cleanly again.

At idle in the water it cuts out sometimes, but when it restarts its fine and runs cleanly, again for about a mile and then if I back off it starts to bog down.

Any ideas guys...

 

[mikidymac]

I am no 951 expert but I know that these do have a throttle position sensor built into the throttle cable and if it is not adjusted correctly it can cause some issues. It needs to be checked anytime the throttle cable is removed or carbs are removed for cleaning.

I am sure the squirrel will chime in.

 

[Sportster-2001-951C-Stock]

It it runs fine for about a mile, this makes me wonder if it's overheating. But the rest of this sounds like a carburetor or fuel system issue. No carbs were offered or used as late as '09 though so must be a DI 951? In that case could be RAVES sticking, opening late or possibly throttle position sensor issues?

If this is an '09 951 DI, it must be one of the last for sure?

If this is a carbed ski, like it sounds, a defective throttle cable mounted throttle position switch I feel is unlikely that will cause a bog or poor performance at low throttle angles. The reason is, this switch makes at 80% throttle and adds "up to" about 10 degrees of ignition advance. Typically this switch fails "open" but I suppose it could fail "closed" and not sure what happens in that case. You can unplug it to see if there's any improvement but if this is actually a carb/fuel issue and you know for sure the fuel lines aren't leaking air (often the fuel/water separator cup o-ring is the cause) then it's unwise to run with a lean mixture as your description leads me to believe b/c this can roast your pistons and rings due to excess heat and almost no amount of extra oil or lack thereof can compensate for overheating pistons due to lean detonation.

That is, never continue to run any 2-stroke with lean fuel mixture due to fuel system issues, fix the problem otherwise pistons are at risk. A cooling system clogged with sand will cause overheating too, and too much heat (for whatever reason will destroy the oil film on the cylinder walls and cause piston scoring, ring seizures, partial seizures, etc., which will feel like power is dropping off.

A big clue for fuel system issues is if they occur before the engine has time to heat up, I guess after a mile the engine is fully warmed and if the cooling system is plugged it would be overheating by that time. Heat will cause power loss due to the oil film fails when there's too much heat.

Regardless, I feel this issue needs to be understood and corrected else your engine is likely to lose it's good health.

You didn't mention any of the history of this engine, like specifically the compression you measured, but if it's a new replacement then I'd say whatever ate the previous engine is also eating the new engine.

That's about the extent of my thoughts, absent more complete info. Could even be your jet pump is seizing up for all I know, but less likely unless traveling this mile takes an hour.

 

[jammin777]

could be raves sticking open. easy to check and go from there. just pop off the rave caps and open and close raves by hand and make sure the operate smoothly. if not clean them. stuck open rave will cause a bog like you have. also when you put the rave caps back on make sure the raves close. if not, replace with oem only rave bellows. there are x brands out there that are stiffer causing the raves to not close. if all is well move on to somthing else.

sportster makes some good points as well.

 

[richie0270]

Thanks Guys for the input.

It is a carb'd ski, I was also writing something else at the time and got the dates mixed up. Its a '98 GTX LTD.

Compression checked and they are both good, I think, both around 135.

Doesn't seem to be overheating, engine gets hot, but not excessive, water circulation is good.

I took one of the RAVE Valves off today and it was full of black gunk, so I'll take them into work tonight and give them a good clean out.

I also took the one off the exhaust today and cleaned that out too.

I'll get the RAVE valves back on tomorrow and then hopefully give it a run on the water at the weekend.

Any more suggestion would be welcome too.

Cheers, Richie.

 

[purple_people_eater]

have you cleaned and rebuilt the carbs? is your accelerator pump working?

 

[Sportster-2001-951C-Stock]

Thanks Guys for the input.

It is a carb'd ski, I was also writing something else at the time and got the dates mixed up. Its a '98 GTX LTD.

Compression checked and they are both good, I think, both around 135.

Doesn't seem to be overheating, engine gets hot, but not excessive, water circulation is good.

I took one of the RAVE Valves off today and it was full of black gunk, so I'll take them into work tonight and give them a good clean out.

I also took the one off the exhaust today and cleaned that out too.

I'll get the RAVE valves back on tomorrow and then hopefully give it a run on the water at the weekend.

Any more suggestion would be welcome too.

Cheers, Richie.

Yep, RAVES stuck open will cause all kinds of poor running at low speed. I check my fuel line for leaks by removing the fuel line from the fuel pump and pressurizing it backward towards the fuel tank. If you turn off the reserve valve and do this, you can test the fuel/water separator cup seal that often leaks.

Are your carbs originals, I think the throttle butterfly shafts on the early 951's were horizontal? The reason I ask is if they came from somewhere else it might be they were incorrectly jetted.

Keep us informed if the problem wasn't resolved, we keep working on this stuff till the problem is solved.

 

[jammin777]

let us know when you get her fixed

 

[SabrToothSqrl]

The external rectifier kit was to replace broken ones on the RFI/DI models... the 1998 951 was built into the MPEM. Why did you do this?

Were the carbs ever modified from factory? What do the plugs look like. You're either missing the spark because the rectifier is not setup right, or the fuel/air is off.

the 98 had a single coil also, not a dual coil setup. so could you be running on a single piston by accident?

 

[richie0270]

I had a 12volt low problem with it so I found an adaptor on your side of the pond, I think it may have even been from OSDparts,

OSD External Rectifier Harnesses - Sea Doo 947 Carb Models
http://osdparts.com/index.php?main_...ing_info&cPath=595_123_189_194&products_id=45

This seem to fix the 12v low instantly.

The carbs have never been messed with and the fuel lines are still original and are clean inside.
Speaking to a few seadoo agents, it seems we don't seem to suffer the same problems as you guys over there, ie green gunk in the fuel lines..

Sparks plugs are a good colour and even, not oily or lean.

Coil pack is putting out a spark to both plugs.

After stripping down both RAVE valves, they were both full of black gunk. Now all clean they are working correctly.

I think I need to get it out on the water again to see if they have made any difference...

 

[SabrToothSqrl]

The green goo comes from politicians who wanted votes from people in corn growing states... and it's called ethanol fuel, and don't get me started on that!

Yea OSD parts sells good stuff, but 12v low on a carb model usually means something is wrong with the stator/magneto.

Do you have the factory service manual? Are you able to test the resistance on the stator?

I'm thinking you may have an electrical issue. Unfortunately on the GTX hull you'll have to pull the pipe to get to the stator.

I hope the RAVEs being clean fix it, but I'm leaning towards an underlying electrical issue...

When you were getting the 12v low, would it still run to the proper RPM? (7,000 ish) in the water.

Can you remove the rectifier parts for another test?

What voltage are you seeing from the battery with the ski OFF?

With the ski ON at 4,000 RPM? (out of water is fine) just don't run more than 20-30 seconds.

have you trimmed back 1/4" inch on the plug wires to get a fresh connection?

 

[Sportster-2001-951C-Stock]

Green goo is our gift from politicians in exchange they ride ethanol stocks up and down each time they change the law or increase subsidies.

"The carbs have never been messed with and the fuel lines are still original and are clean inside."

Never since 1998, this is impossible, unlikely even for good fuel???? This is #1 problem killer of 2-stroke engines, lean condition from plugged carbs.

 

[DAGRE147]

Green goo is our gift from politicians in exchange they ride ethanol stocks up and down each time they change the law or increase subsidies.

"The carbs have never been messed with and the fuel lines are still original and are clean inside."

Never since 1998, this is impossible, unlikely even for good fuel???? This is #1 problem killer of 2-stroke engines, lean condition from plugged carbs.

I think it's because he's from another country, no ethanol in their fuel

 

[Sportster-2001-951C-Stock]

I think it's because he's from another country, no ethanol in their fuel

Hence it likely won't need a carb overhaul for at least another 17 years or more?

 

[DAGRE147]

Oh no I misread your quote, i was just talking about the fuel lines not the rebuild. My bad!

 

[Sportster-2001-951C-Stock]

I agree about our fuel causing more problems for carbed motors, kinda surprised europe doesn't use oxygenates in their fuel too but emissions over there are all about CO2, which means they're trying to squeeze more out of every drop of fuel by lightening the load and installing puffers.

This might be a good opportunity to point out a lean hesitation is quite likely caused by restricted transition ports, these aren't by coincidence the smallest passages in the Mikuni carburetor.

 

[seadoonewb23]

i have a 951 le di it is throwing p0230 code which is Fuel Pump Primary Circuit Malfunction and am stuck in limp mode. Also right before limp mode i started having idling issue where it would stall out on me but run strong anything above idle and never cut out. I have new fully charged battery. I just replaced fuel pump I am still getting the 2 second beep every minute. Does fault code need to be reset? What else would cause this fault code? Also it still will not idle. All help much appreciated.

 

[mikidymac]

Start your own thread please.