99 sea doo gti questions

sptjet90Reflexx

Petty Officer 1st Class
Joined
May 28, 2011
Messages
383
Just got out sea doo back from the repair shop about 3 weeks ago. They had been sitting in covered storage for almost 3 years with no use. The storage was on the repair lot and they were regularly winterized.

List of things repaired included new or rebuilt carbs, new fuel lines, cleaned fuel tank.

Took her out on the water and she seemed to take longer to start then I remember.. But once she was running it ran great for the last 2+ weeks. Except the gas gauge stopped working after the first day..

Fast forward to yesterday. Me and my son were out on it and it just was not running right. Sounds more grunty then usual. and also appears to be a 10mph top speed loss (using the boats speedo which I know is not accurate). It usually stays around 50-52mph now it wont go past 40. Very sluggish coming out of a spin.

So I pulled her out on the trailer to check the impeller and just do a general visual inspection. I took the seat off and found a water leak on the port side coming from what looks like the intake manifold. it just sprays water into the engine compartment while running.

Anyone have an idea?
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
7,952
Had the same model and year and had the same problem. You've got loose bolts on the manifold. They will need to be removed, locktited and re-torqued. Mark them so you mknow when they start to come loose again. m If they do, you have a bend driveshaft causing vibration.
 

sixfigures

Petty Officer 2nd Class
Joined
Nov 4, 2013
Messages
115
also check for broken motor mounts those will allow the engine to jump all over the place and loosen the bolts. it is a very common problem with that model
 

sptjet90Reflexx

Petty Officer 1st Class
Joined
May 28, 2011
Messages
383
Replaced the wear-ring and fixed the speed issue. The hole in the intake manifold was coming from one of the freeze plugs. Some JB Weld fixed that. Then a new problem came up. She wouldnt run WOT without the choke. Pulled the carbs and the gasket the tech used was 1/2 the old gasket and 1/2 RTV.. horrible job. I cleaned carbs and replaced the gasket with a good clean bead of RTV. This fixed the problem. OR SO I THOUGHT.. about a week or 2 later the same issue is happening.. Wont run full throttle without choke pulled to a perfect spot.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
7,952
Rebuild the carb correctly and use a gasket instead of rtv.
 

SpitAndDirt

Petty Officer 2nd Class
Joined
Sep 23, 2008
Messages
103
Have you checked your battery charging voltage per the shop manual? You should not see over 14.5 volts while running it around 3500 rpm. Out of the water under no load, it should run that fast. Voltage regulators tend to go bad after all these years and when they go bad, they exhibit the kind of running problems you are experiencing. As long as your internal carburetor micro-filter is clean and your water separator filter is clean, then I would be looking elsewhere. This also assumes that your oiling system is functioning properly and your engine has good compression on both cylinders.

It would be simple enough to disconnect the voltage regulator which is bolted to your MPEM computer and just run it for 10 minutes on battery power alone. It may solve your partial choke issue, and possibly your top speed issue too.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
7,952
If the voltage is too low the battery will go dead. If its too high you'll boil out the battery and have acid all the place. Neither those problems were reported.

Sure sounds like a carb problem. The high speed adjustment is off. If its sealed drill it out and make it adjustable.
 

SpitAndDirt

Petty Officer 2nd Class
Joined
Sep 23, 2008
Messages
103
If the voltage is too low the battery will go dead. If its too high you'll boil out the battery and have acid all the place. Neither those problems were reported.

Sure sounds like a carb problem. The high speed adjustment is off. If its sealed drill it out and make it adjustable.

Not always, from my personal experience the voltage regulator will fail and allow A/C current to bleed into the D/C charging circuit. This messes with the computers ability to function properly and fire the coil with accurate timing. I tested this by using my oscilloscope to view what the charging circuit was doing.

Here is my thread over on pwctoday where I posted pictures. http://www.pwctoday.com/showthread.php?t=126014&highlight=voltage+regulator
 

sptjet90Reflexx

Petty Officer 1st Class
Joined
May 28, 2011
Messages
383
I tried the ski again without changing anything and same thing. I cut her off, unplugged the regulator and fired her up. Same thing no change.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
7,952
Not always, from my personal experience the voltage regulator will fail and allow A/C current to bleed into the D/C charging circuit. This messes with the computers ability to function properly and fire the coil with accurate timing. I tested this by using my oscilloscope to view what the charging circuit was doing.

Here is my thread over on pwctoday where I posted pictures. http://www.pwctoday.com/showthread.php?t=126014&highlight=voltage+regulator
I follow your logic and agree it would cause runability problems. It's the statement about tweaking the choke that sets the tone I think. To me that indicates a fuel problem, not an electrical one.
 

sptjet90Reflexx

Petty Officer 1st Class
Joined
May 28, 2011
Messages
383
I am going to town in a bit anyway. I will pick up some new plugs for her and see if it helps at all.
 

SpitAndDirt

Petty Officer 2nd Class
Joined
Sep 23, 2008
Messages
103
I follow your logic and agree it would cause runability problems. It's the statement about tweaking the choke that sets the tone I think. To me that indicates a fuel problem, not an electrical one.

If it didn't happen to me, I would totally agree. When my regulator decided to misbehave on the water, I was able to get the engine to run decently(but far from perfectly) by tweaking my choke about halfway.

It's completely baffling to me that by pulling the choke out about halfway with a faulty regulator would alleviate some of the problem. But at this point, if the OP isn't having a charging issue, then I completely agree that going back into the fuel system for further investigation is the next step. Unplugging the voltage rectifier/regulator is cheap and quick. It's just where I would have started to begin troubleshooting because it's so easy to do and it's a known problem on the older two-stroke Sea-Doos.

To the OP, have you downloaded a service manual for your ski yet? They're free! www.SeaDooManuals.net

According to the service manual, the LOW speed screw is set at 1 turn out from seated. The HIGH speed screw is supposed to be lightly seated, so zero turns out.

Out of curiosity, have you performed a compression check just to make sure that the motor is still in good shape?
 

sptjet90Reflexx

Petty Officer 1st Class
Joined
May 28, 2011
Messages
383
No Title

I had a strange thought and went to check the ignition water box. It was full of water. Not sure how that happened but I drained it and still no change. I did a plug pull with brand new plugs and the plugs show its running a tad Lean I would say..
 

Attachments

  • photo209462.jpg
    photo209462.jpg
    24.5 KB · Views: 0

sptjet90Reflexx

Petty Officer 1st Class
Joined
May 28, 2011
Messages
383
um interesting development.. I went to re-set the lowspeed adjustment then fired her up and adjusted till she was idling smooth. Pulled the plugs and went to do a compression check. Tested mag side still same around 150psi, went to test pto side and when I pressed the starter a gyser of water started shooting out of the mag side.. WTF just happened? Did some kind of slowly leaking gasket finally give up? I pulled the ski out and drained the water in the cylinders and fired her up without water.. took a moment but she is running again.

I am thinking some gasket on the cylinder cover blew..
 

SpitAndDirt

Petty Officer 2nd Class
Joined
Sep 23, 2008
Messages
103
I had assumed you found the problem. Since you bumped, I'll answer: your lower base gasket could have blown out. Both externally and internally.

I have no idea why or how this could happen, but the only way to verify this is to pull the cylinders off. Easier done with the engine removed.

Now if you just want to check the head seals, that can be done with the motor still in the ski. The head gasket is only a couple of o-rings. Now here is the kicker: You stated that you have 150 psi on both cylinders, so if this is the case I doubt that your head gasket o-rings have failed, which now leads us to the lower, paper, base gasket failing.

Is this a rebuilt engine? A short block from SBT? If you look between the cylinders at the base gasket, is it green or black?
 
Top