951 GSXL advice please

[Colin GSXL]

Got a 97.5 ski that I bought as a non runner. Carbs were leaking fuel into the motor and the fuel switch was bypassed.

I've replaced the fuel line components and replaced the worn needles and seats.

Motor now not filling with fuel and starts up easily but won't run right. These are the symptoms....

Running on hose the PTO cylinder seems to run fine but the front seems very lean - motor ranaway a couple of times.

Put ski in water. Started fine and idled about 1200 (I did adjust throttle screw when carbs were off). Tried giving it gas and it got to about 3200 and would go no faster.

Pulled plugs (new) - PTO plug was coloring up nicely but Mag plug looked new (wet with oil). Also I could feel heat around the PTO cylinder but not the Mag.

Good spark to both plugs (trimmed Mag lead back but was not needed).

Stripped Mag carb and checked low speed jet, etc. No blockages. No change to hose running.

Checked pop off - about 24 psi.

Compressions - 150 both cylinders.

Reeds looked OK from a visual inspection - should I pull them and look closer?

Carb. regulator diaphragm has no signs of damage / holes but not sure what it should look like new so should I change this?

Any thought / suggestions on what the problem with this ski is would be appreciated.

Thanks

Colin

[Bryan Glynn]

What pop-off are you running, what jets and screw settings?

[Colin GSXL]

2.3 N/S (stock springs)
90 lows
170 Mains
R&D F/A

Lows 1.5 turns out

Highs 1 turn.

[ August 15, 2002, 02:05 PM: Message edited by: colin95xp ]

[Bill O'Neal]

No wonder it won't run right. Set the high speed adjuster at zero turns out. Your front clyinder is having the flame (spark) wetted out and not firing. That clyinder is way too rich.
I don't even go that far out using a Coffman pipe at 7400 rpm.

I run similiar jetting, but less main jet, at Zero turns out mag, 1/16th out pto, without any lean problems.

[Colin GSXL]

Thanks for reply Bill

I am currently putting back the stock jettings and flame arrestor to try and get ski running in it's 'stock' form as I've not had the ski running properly since I bought it. I figure the best approach is to 'prove' the motor is good in standard form and then start 'tinkering'!

I bought the R&D flame arrestor and outerwears as I have heard the horror stories about water ingestion and I ride on the sea so want to protect the motor but perhaps I was running when I should have been walking.

Colin

[Colin GSXL]

Update.......

I put back the stock jetting and airbox and the ski seems to run fine on the hose - hope to try it on water tomorrow. It's definately running on both cylinders judging by the heat around both cylinders - there was none on the mag cylinder before. Hopefully jetting was the problem.

Another fault on this ski is the throttle cable tps is defective. Reading the manual on the ski it seems the tps only operates at 80% throttle and activates the solenoid that puts a vacuum on the carb. regulator chamber therefore leaning out the mixture at high throttle settings. On this basis I guess the ski should run OK (a bit rich maybe) with this disconnected. Am I correct in this assumption and that the RAVEs are controlled independently by the mpem. This setup seems to be exclusive to the 97.5 GSXL and was changed for later models.

Also Bill if you read this - what jetting would you suggest for this ski in stock form with R&D F/A. Looking for hole shot benefits as most of my riding is on the sea so top end is not so important.

Thanks.

Colin

[Bill O'Neal]

Using just an R&D filter without ANY other mods, I'd open the high speed adjusters a quarter turn or less, then set my lows to whatever is necessary to get a ggood holeshot without bogging or hestiating. The R&D filter is somewhat restrictive and not as free flowing as some of the other filters on the market.

[Colin GSXL]

Thanks for advice Bill, I will give that a go. Do Outerwears make any difference. I guess they will just add to restriction if anything.

Good news - took ski out earlier with original jetting - ran fine.

Thanks again.

Colin

[Bill O'Neal]

I typically see a loss of rpm on an otherwise well jetted boat when I install Outerwears, so yes, they are more restrictive. Makes perfect sense.

[Colin GSXL]

The saga continues..........

Ski ran fine with original airbox and jets / settings. I then put on the R&D Filter, wound out the highs 1/2 a turn and took the ski out. It ran great with just a very slight hint of hesitation on take off so I wound the lows out 1/8. Rode the ski on the sea (bit choppy so no long WOT runs. One time is seemed to loose idle speed and did not want to rev. Motor cut out. Restarted it and it ran fine for the rest of the day.

Took ski out this Sunday and it would not idle. Normally runs at 3k out and about 1400 in the water. If I gave the ski gas it would cough and splutter a bit almost dying but by feathering the throttle I could get the revs up and then it would fly. Sea was very rough and as the ski would only run sweet at higher throttle settings I gave up for the day. Before taking it out of the water I changed the plugs but this made no difference. Also disconnected the RAVE solenoid but that made no difference to idleing.

Today I had a look at the ski and found the following............

At idle motor only seems to run on front cylinder. Rear plug just gets oily and after running the motor for a few secs I can feel heat around the front pot but not the rear.

I checked spark - strong on both leads (swapped leads also to prove it's not ignition).

Compression 150 on both.

Pulled carbs and stripped regulator cover on rear carb. No blockage in low speed jet. Diaphragm fine. Needle / seat opens smoothly.

Checked reed valve and raves - fine.

I turned mixture screws to factory settings and tried stock airbox - no difference.

I noticed that by putting my hand over the carb when the ski was idling (1100 out of water) it pulled fuel in (acting like a choke I guess) and revs briefly rose to 3k but then died back to 1100 after a second or 2.

I am guessing it's a carb problem and will have another go tomorrow but if anyone has got any suggestions or has come across this type of problem I would appreciate your help.

Sorry for long post.

Colin

[Colin GSXL]

Never mind - sorted it - was a blocked low speed jet.