'96 GSX won't 'hard' accelerate

[oldbuck]

'Un-retiring' a pair of '96 GSX's we bought new back then that have sat idle for a few years. One runs great, the other is having an odd issue with acceleration.

When I roll the throttle on gently it will run right up to the rev limiter and can stay here all day, but when I give it a handful of throttle it doesn't die, but immediately goes into what I'd call 'diesel' mode - a slow off sounding idle. I let off the throttle and let it idle for 30 - 45 secs and then it'll come right back to life, unless I give it a handful again and the diesel process repeats. Roll on the throttle and the boat will run all day. The problem is very repeatable - it will do it every time the throttle is mashed.

Spark plugs look clean so I don't think it's loading up the carbs, more like it's electrical or getting starved for fuel.

With 2 GSXs it's easy to trouble shoot and swap parts - I've tried the easy ones - coil, mpem, regulator with no change.

Could it be fuel starvation? the diesel scenario is immediate with throttle mashing, not say after a carb bowl worth of fuel has burned through.

Any help would be greatly appreciated!
-dave

 

[LouDoo]

It sounds like a fuel delivery problem. Do you still have the grey tempo fuel lines? I would check the main fuel filter, carb. filters. Here's a link that explains more.

http://www.seadooforum.com/showthre...el-Delivery-Problems-low-revs-bogging-surging

Lou

 

[Dr Honda]

Is the engine revving up , and bouncing off the rev-limiter? That would sound like stuttering engine. (like you are describing) If you have very bad cavitation... the ski will hardly move... but it will allow the engine to rev free. (to the point of the ignition cutting out to control it's RPM)

OR...


is it truly not going past 2500 (or so) RPM?

 

[oldbuck]

It sounds like a fuel delivery problem. Do you still have the grey tempo fuel lines? I would check the main fuel filter, carb. filters. Here's a link that explains more.

http://www.seadooforum.com/showthre...el-Delivery-Problems-low-revs-bogging-surging

Lou

Excellent link Lou - Thx! I've hit most all the 'easy' items except checking the one-way valves - thats something new on me. The boats are all original, hence original fuel lines so that may be where I head next...

Is the engine revving up , and bouncing off the rev-limiter? That would sound like stuttering engine. (like you are describing) If you have very bad cavitation... the ski will hardly move... but it will allow the engine to rev free. (to the point of the ignition cutting out to control it's RPM)

OR...


it it truly not going past 2500 (or so) RPM?

Good Question Tony - It pulls well all the way up to ~7k rpms. (Still makes an old guy grin;-) No cavitation issues - flat water and likely in the 50 mph range at WOT. It will run at that speed until I get tired... Rode it about 15 miles the other day at 5k+ rpm. Just can't hit the throttle hard or she shuts down to a low idle. Issue seems closer to the 'bog' described in the link Lou posted.

 

[oldbuck]

maybe a dumb question, but is there a filter in each carb? I took out the filter in the forward carb and it was pretty gummed up - getting to the back carb (if it's got a filter) looks a little more challenging... was hoping not to have to tear *everything* apart.

-dave

 

[ski-d00]

yes, filter in each carb. not difficult to separate the carbs.

 

[oldbuck]

thx ski-d00! you're right it looked much harder than it was - and the back carb filter was even worse than the front. I have no idea how *any* fuel was getting through it!

test ride tomorrow and we'll see if they were the root cause of my bog.

-d

 

[oldbuck]

Well cleaning the in-carb filters has totally resolved my bog problem - Thanks for all the great support SeaDooLou, Dr. Honda & ski-d00!

 

[built2prfctn]

Is there a write up to doing this myself? How hard is it to clean the carb filters?

 

[oldbuck]

Is there a write up to doing this myself? How hard is it to clean the carb filters?

1st time I've done any carb work on my sea-doos - I'm not a mechanic - it was easy. Link to the procedure was posted by SeaDooLou above.