2002 FX140 bogging - PWC Forum: The best hang-out for Personal WaterCraft enthusiasts

DAdams · 08-16-2011, 12:36 PM

Hi- We're new to jet ski's and recently bought an '02 FX140. Had it out and it ran pretty well overall. It did die a few times while idling. However as we are new to jet ski's I do not really know what to expect for performance.
When running on the hose at home I've noticed a substantial bog when hitting the throttle off of idle. It does the same if I nail it from mid range RPM. If I ease or feather the throttle it will accellerate ok up to about 8000 RPM. I changed the plugs and it idled better. Did not change the bogging problem though. I took off the air cleaner and flame arrestors to try it again in case they were oiled up but still no better.
I've read everything from bad TPS, dirty pump filter, dirty injectors, and more but not really sure where to start in what order. BTW- No error codes on dash. Thanks for any advice...

Ernest T · 08-16-2011, 06:43 PM

You should be seeing 10000 rpms. I suspect 1 cylinder is not firing or not getting fuel. Run it then pull the plugs and look for a wet one or one that looks new (wet = no spark possible bad ignition coil or bad wire, dry = bad or clogged fuel injector). Be sure there is not a loose connector to the ignition coils. Try jiggling wires while its running.

DAdams · 08-16-2011, 07:35 PM

Ernest- Thank you for the reply. Tomorrow I'll do what you've recommended and report back.

Thanks again.

DAdams · 08-18-2011, 11:59 AM

Ernest- I pulled the plugs and do not see any wet or oiled ones. This is only after about 30 minutes total of running them on the hose at home. Two were just turning carmel with the plating on the electrode starting to turn dark. The other two were a bit "newer" looking with the electrode plating still fairly bright. I did plug each back into the wire one at a time and turned the motor over to check for spark. Each was firing. Not sure how bright of a spark to expect. It certainly was not as much so as an automotive spark.

What next? Fuel? Clean pump and injector filters or try running some SeaFoam through it?

Thank you.

Ernest T · 08-18-2011, 02:16 PM

The simplest thing would be to run some injector cleaner through. Yamaha makes a product called Ring Free Plus that is really good if you have a dealership close by. If not, you might try SeaFoam or an additive from the auto parts store with Techron. I'd run a tank with the additive, and you might want to use premium since they usually have more detergents.

There is not a filter that I know of, just a screen on the input of the fuel pump and little screens in each of the fuel injectors. They do occasioinally get clogged with debris. You can also check the injectors with a multimeter while you have them out. I'll try to find the numbers to look for tonight.

If all that does not solve the problem, I'd do a compression check next.

DAdams · 08-23-2011, 08:19 AM

I went ahead and checked compression as it was the simplest thing to rule out. I got 165-178 between the four cylinders. This was cold so my numbers should be better if it were hot. I read where Yamaha states a minimum of 157 with a warm motor so I assume I'm ok with compression.
I've got the trottle body assembly out and I'll ckeck injector resistance and clean screens tonight.
A couple of questions please.
- What is best to clean screens? I'm read somewhere not to use carb cleaner.
- The manual states not to reuse the injector seals. Is this true? If so I'll order a set.
- What else should I bench test while I've got it torn apart?
- On a less critical note. Some of my hose clamps in the bilge are getting pretty corroded. What do most use when replacing. I can order the original spring type from Yamaha or are the stainless worm gear band clamps a better replacement.

Thanks again for all the help...

Ernest T · 08-23-2011, 07:14 PM

I'd recommend taking the injectors to a dealer and let them do the cleaning. They can flow test them to make sure they are up to specs. My dealer does them for $23 each if you bring them in. Otherwise, the best way is to put them in an ultrasonic bath.

I don't know about using carb cleaner on the injectors.

There was a problem with the hose clamps on certain model skis failing and the dealerships replaced them for free, but I don't think the recall included the FX 140. I'm not sure what clamps they replaced them with. I don't like those spring clamps. A lot of guys like the Oetiker type clamps you can find at some auto-parts stores.

If the seals look OK you can reuse them, but be sure they are not dried out and brittle.

I hope you get it fixed.

DAdams · 08-24-2011, 08:45 PM

Ernest- Pulled the fuel rail off the throttle bodies. Do you simply pull each injector out of the fuel rail? They seem very tight and don't want to break anything so I thought I'd ask. Going to go and have them cleaned.

I got 52-53 ohms with my meter. Manual states 40-50 ohms at 68F. It's pretty hot down here in Texas. It's around 90F at 8:00pm. How does this sound to you?

Thank you...

Ernest T · 08-24-2011, 10:10 PM

I've only done it on an FX HO and the injectors came out with the fuel rail. Then I pulled them off the rail. There is an "O" ring inside the fuel rail end that may be holding them in, and this is the ring that may need to be replaced if yours are stuck. Maybe you could spray something around them to help loosen it up. There is another ring that is wider that Yamaha calls a grommet that is on the throttle body end of the injector, and that part can usually be reused.

I don't think I have the right manual for your FX. Mine says 14-15 ohms is what you should get at 68F.

Good luck.

DAdams · 08-29-2011, 12:13 PM

May be making some progress. Injectors were pretty ugly and plugged up. Had them cleaned Saturday. Before cleaning two were flowing at 50-52% and the other two around 60%. Will try them out in a week or so as I have other parts on order to install first. If I may put in a plug for InjectorRX here in the Houston area I would highly recommed them. He is extremely knowledgable and will let you look over his shoulder if you bring them in for his "while you wait" service which is few bucks more than his standard $18.00 each for a turnaround of a few days.

While at it I checked the screens on the bottom of the fuel pump and all is clean. Being a PWC novice I have a question on the check and rollover valves. Their description pretty well explains their purpose, however I CAN get a slight amount of air through the end of the check valve that should be closed. Is this a problem and what would the symptoms be if one were bad? Just curious if it could relate to some of the problems I've been experiencing. Hopefully all is good however when I install the cleaned injectors.

Thanks for the help...