2001 GTX DI - Fuel Pump

[Grast5150]

Morning Everyone,

I wanted to share my recent experience with my Sea-doo 2001 GTX DI. My youngest drove the ski off the lake telling me it was surging and had no power. As we all know, DI can be a little finicky and they required 107 PSI Fuel Pressure, 80 PSI of Air, and Good Spark. After I took the ski out and noticed the following symptoms.

- No Power
- RPMs no higher than 3500
- Extreme Surging from 2500 to 3500 RPM
- WOT caused engine to die

So, the day was done and took home to diagnose. Once I started the ski, It performed as expected with normal idle and was able to get up to the 6000 RPM range. So......inconsistent Wonderful. My initial thought was something wrong with the Air side as the fuel pump was basically new with less than 40 hours on it. I was also noticing a gurgling noise on the fuel rail. So, I started diagnosing. I first verified the air rail had 80 PSI at start and through throttle range. Air Checked good. The next step was testing Fuel Pressure. The manual states that with key inserted, fuel pump should run and show 27 PSI. I noticed that while pump was running it was at 27 PSI but after 2 seconds it turned off. The fuel pressure immediately started to drop and could hear the gurgle sound. If the rail does not hold pressure before engine start, That is a faulty Fuel Pressure Regulator. I replaced the regulator and resolved the pressure drop. I thought the issue should be solved and took out on the lake. Short story....NO!

Back to testing and more fuel pressure testing. Fuel pressure should be 27 PSI at key insert and 107 PSI +- 2PSI when running. When I tested the ski, All of these numbers were correct, So cant be the fuel pump. On a hunch, I put water on the ski and kept it running. This is when I noticed the true issue. The fuel pump would start off at 107 PSI but after 5 minutes pressure had dropped to 100 PSI and after 10 Minutes dropped to 92 PSI and the engine stalled. So, the fuel pump was the issue. So I pulled it out in order to inspect.

See attached picture. This is a Quantum Fuel System Fuel pump. As you can see it is bent at the fitting which was causing a loss of pressure during operation. My only thought is that movement of the ski with the pressure of the spring caused the fitting to fail. I have to say that Quantum is honoring their lifetime warranty. My goal of this post is that physical inspection of the fuel pump should be done if you have any issues which appear to be fuel related.

Thanks.

 

[WaarrEagle]

Thanks for posting. It is rare to see people follow the tried and true troubleshooting steps with a DI. But you did and found your issue.

 

[etemplet]

What model pump is that. I have read of successes replacing with aftermarket but only with one specific model.

On a side note, I think the DI is the most BAD azz 2-stroke in the barn.

 

[Grast5150]

What model pump is that. I have read of successes replacing with aftermarket but only with one specific model.

On a side note, I think the DI is the most BAD azz 2-stroke in the barn.

The unit in the picture is Quantum HFP-342DI. However, it is no longer sold. I have another DI which uses the better Quantum HFP-501DI. It is unibody design very similar to stock which does not have the fitting of 342DI. I would recommend the HFP-501DI as it is as direct as replacement to stock fuel pump on the market. No more splicing of wires and it feels very sturdy.

Thanks.

 

[Grast5150]

Thanks for posting. It is rare to see people follow the tried and true troubleshooting steps with a DI. But you did and found your issue.

Thank-you, I know that DIs have a bad rap but in my opinion they are the best of any 2-stroker. You just push button and they start whether cold or hot, they do not stink like most 2-strokes, and have lots of power. But I will admit they are the most expensive 2-stroke anyone will operate. The 2-Stroke Full Synthetic Oil is about 75 dollars a gallon and use of cheaper oils will result in one thing....damage to the engine and reduced life. Most consider the biggest limitation is the wear of the engine which is about 250-275 hours. Here is the rub though, If you use OEM 2-Stroke Full Synthetic Oil, The crankshaft will last and the top end will only need a 25 thousand bore out. A typical head can take upto 8 25 thousands bore out before sleeving. So lots of life

I look at it this way. Most people put 50-60 hours per year on their ski. That is 5 years of good use before needing to rebuild the engine.

All 3 of my DIs had one common issue, OIL STARVATION. My 1st DI, the oil lines melted on the exhaust because manufacture made them too long. It destroyed the Mag cylinder and had to sleeve it. 2nd DI had a good life of 260 hours, but the last owner used cheap 2 stroke oil in the last 50 hours which congealed in the oil tank and caused the PTO cylinder to loss half of it life. 3rd and final only has 100 hours and once again used cheap oil. It cause prematured failure of the counter balancer shaft which failed and broke the case.

So moral of story is dont use cheap oil.

If you use the right oil and dont sink your ski, the crankshaft should last 500 hours before needing a rebuild and the top end is good for 250 or so hours. If you can do they work yourself, I think DIs can be good projects. If not so handy, I would suggest one of the older 4 strokes.... They have come down in price these days.

Later.

 

[etemplet]

If people world ride these ski even 30 hours a year they would have less problems. Most people just let them sit and they are lucky if they get on the water monthly. Glad to hear a definitive report on the DI engines. So much mis and dis- information out there.

 

[mikidymac]

@Grast5150. This is great news for the DI fuel pumps. I hope the lasting solution is the HFP-501DI. I am so tired of telling DI owners the only solution is a crap shoot, used OEM pump.

And I would be lucky to get 5-6 hours per year on each ski, let alone 50-60.....