• This site contains eBay affiliate links for which Sea-Doo Forum may be compensated.

Fuel gauge not working(not the usual problems)

Status
Not open for further replies.

Bradmxz

New Member
Hey I just got a 95 sea doo sportster with the 657x engine. Boat isn't in bad shape. Just trying to work out a few bugs. The fuel gauge doesn't work. Also there aren't any beeps. Checked the fuses and replaced the broken ones. The fuse for it wasn't broken by the way. It just sits there showing empty. Any help or suggestions is much appreciated
 
Moat of the time, fuel gauge malfunction is due to the fuse mounted inside the fuel tank. Is this the fuse you checked? I suggest jumping it out if you happen to go back in there, I covered my blown fuse using a solder bridge, a short piece of wire soldered across it would work as well.

The fuse is inside the fuel pickup baffle on the PCB, but before pulling the pickup baffle out of the tank you can confirm if the gauge works 1st by jumping out the 2-wire connector going to the gauge at the tank and powering on the MPEM, the gauge should read full scale. If not, suspect gauge or gauge wiring.
 
Ok thanks. I will try that. Yesterday though I found a bigger problem. The boat ran fine for about 15-20 mins. I shut it off in the middle of the pond. It wouldn't start back up. I rolled it enough that the battery went dead. I inspected the plugs and they were dry as a bone. With that much rolling they should've been soaked in fuel. Any ideas where to check that out first. I checked the fuel filter and it was full. Doesn't make any sense as to why it would run fine for so long and then nothing
 
I've removed the air box and and found that the butterflies weren't returning to the fully closed position. I don't think this is the total problem but for sure a contributing factor
 
If the butterflies don't return to the idle position, the engine speed will/could be very high. You weren't having this problem?

As far as running 15 minutes then running out of fuel, this could be the fuel tank air vent check valve is stuck and needs cleaning. As the engine runs and consumes fuel from the tank, makeup air must enter the tank through the check valve in the vent tubing else a partial vacuum builds inside the fuel tank. Eventually, the fuel pump will be unable to overcome the partial vacuum.

A quick test is to loosen the fuel filler cap and see if this restores fuel flow function.
 
YES that was my thought yesterday as well. Unfortunately by the time I thought about it the battery had been drained. The idle speed should have been up. I noticed it was time a long time to come down to compared to what it should take.
 
Last edited by a moderator:
My idea now is to try and run the engine from a gas can to try and isolate the problem. Which line on the carbs is the feed and which is the return. It seems like the vent is in the fuel cap on my boat is that correct?
 
I forgot to mention on the fuel gauge, there's a fuel level float with a magnet or two on it and sometimes this hollow float inside the fuel pickup will sink id the air inside escapes, and/or sometimes they slip out the bottom and float around freely inside the tank if the bottom screen cover dislodges from the baffle.

So make sure the float is there and isn't full of fuel (sinking), but I still recommend soldering over the fuse.

While the baffle is out of the tank and before sliding it back into the tank, turn baffle upside down to cause the float to move up scale to make the magnetic reed switches, power on the MPEM, and you should observe the fuel gauge moving up scale as the float position nears the top pf the pickup baffle.

Of course, if the fuel tank is empty you'll get a low reading and if it's very full you may have fuel spill into the bilge so be careful.
 
My idea now is to try and run the engine from a gas can to try and isolate the problem. Which line on the carbs is the feed and which is the return. It seems like the vent is in the fuel cap on my boat is that correct?

I'm not sure if the fuel cap on your boat serves as the vent but not as far as I know. I believe there's a separate vent. As far as I know, Seadoo didn't use venting fuel caps and that's pretty unusual for boats and watercraft in general, based on my experience.

Running the engine from a gas can (using pre-mix fuel where applicable) is a valid test IMO, be careful not to spill fuel into the bilge of course.

The fuel supply is connected to the fuel pump, sometimes the pump will be divorced from the engine on some boats, or on the side of the carburetor on others, depending on the model. Pulsations from the engine crankcase are used to operate the fuel pump diaphragm, so you'll see a tube connected from the crankcase to the pulse port on the fuel pump. Leave this as is, connect the fuel tank/can to the inlet port where the fuel tank normally connects.

There's a fuel return on this setup that normally leads back to the fuel tank, so while running fuel will be pumping out of the return and entering the main tank UNLESS you re-route this to the gas can.

But honestly, given it ran okay for more than 10minutes, seems your fuel tank is experiencing a PARTIAL VACUUM so unscrewing the filler cap should alleviate that for testing purposes.
 
Last edited by a moderator:
I agree with you. No they didn't use a vented cap I found the vent. I blew on it to pressurize it and realease the cap to relieve the pressure. Seems to be working ok. I reinstalled to air box and started the boat. Fired right up. I guess the best way to test this would be in the water. Ill try the vent if it shuts off on me.
 
I should mention, if there are exhaust system leaks into the bilge then carbon monoxide builds up in the bilge and will displace oxygen, smothering the engine. Very poisonous and not readily apparent either, you don't want to be breathing that.

Opening the hatch cover, running with the seat off (in case of jet skis) or running the bilge blower for fresh air supply while running the engine are all ways of diagnosing exhaust leak related issues.
 
Well I have confirmed the that my problem is fuel. Unfortunately I done it the hard way. Had the boat in the water and it started acting up so I pulled and depress the choke lever quickly. The boat took off like a raped ape and then quickly seized. Haha. Oh well I guess I find out where the problem is now. I should've taken the carbs off and cleaned them. But hindsight is 20/20
 
Last edited by a moderator:
Sometimes the jet pump will seize due to lack of oil, so remove jet pump to confirm which/if engine is seized.

If not, I guess you were experiencing engine hesitation due to lean fuel mixture? Yes, running too lean will lead to piston damage. and hesitation is the #1 clue of the root cause.

But, every 2-stroke will eventually seize once engine wear becomes excessive b/c compression blow-by will destroy the lubricating film on the cylinder wall and piston will overheat due to excessive clearance.

Also, running too lean (lack of adequate fuel) causes the piston to overheat and this heat causes the lubricating oil film to fail.

In your case, you can remove the cylinder head and inspect the cylinder sleeve for scoring and aluminum melted and smeared on the cylinder sleeve from the overheating piston.
 
Status
Not open for further replies.
Back
Top