Here is the solution to the problem of my Waverunner losing power and not being able to go above 35 mph. I'll start with the problem so you can compare, and then a number of items to check with details and pictures documenting the fix that worked for me.

So I took my Yamaha Waverunner VX 1100 Deluxe out to tackle some big waves and on the way back, it started to make a small sputtering noise and would not go past 35 mph; the sound is faint and muffled, as if something is clogged or not getting through causing it to loose power. Note that I am no mechanic but willing to try anything rather than take it to the shop!

fouled spark plugs on a waverunner

fouled spark plugs

My first instinct was to look at the plugs. I've heard that a good mechanic can tell whats going on with the engine by looking at the spark plugs. As you can see in my picture above, 3 of the 4 plugs look great with the other one being discolored. I passed the picture on to a few experts, did some extensive research on the internet and found a number of suggestions that would cause my Waverunner to loose power, they are:

  1. Check error codes to see if any appear
  2. Weeds in the intake grate
  3. One or more spark plugs are fouled
  4. Low RPM mode has been activated
  5. Most batteries don't play well with waves, check battery voltage.
  6. Clogged air filer, usually oil
  7. Wear ring which surrounds the impeller letting water through
  8. The impeller is damaged
  9. Check plug is receiving spark
  10. Cylinder is bad, check compression
  11. Multi function meter
  12. Fuel injectors (use Lucas fuel cleaner)

I started going down the list above and here are my results.

1) I held down the MPH / VOLT button for 8 seconds and received a code of 1 - 1 means all is normal, so no help there.

2) I checked the intake grate for weeds and it was clear.

3) I replaced the spark plugs and still ended up not being able to get the waverunner above 35 mpg

4) I lost my remote, so I did't have a way to deactivate the Low RPM mode (L-Mode) if that had been the problem. The L-Mode light was not on, but perhaps the bulb could have burnt out? Doing more research, I found that L-Mode limits your engine to about 5,000 rpm. Since my Yamaha Waverunner VX Deluxe was topping out at 7,000 rpm's, I suspected that was not the problem; if it was, I would have had to purchase a new remote from the dealer at around $130.

5) Batteries don't like to be jostled around, and waves do just that. Had I had a standard battery, that could have been a problem, but I have an Odyssey that is made for the waves, so I knew this was not a problem. I documented info on my Waverunner stalling, which includs in-depth details about using the right battery; in that article, it was part of my problem, but there was more too it, so check it out if you're having an issue with stalls.

6) Air filter's will clog when you fill it up with too much oil - it's a common mistake Yamaha owner's make by checking the oil cold - you need about 5 minutes hard run time before you can get an accurate reading or you'll overfill and end up getting it in the filter. I took pictures of what the air filter looks like clogged with oil in the stalling docs I refer to above. In this case, the air filter was fine. Note: you can only get about half the oil out of most older waverunners when you drain it, so make sure you fill only as much as you drain plus whatever was low, or you'll overfill ;)

7) I read somewhere that the "wear ring" which surrounds the impeller can erode and let water through, I looked at my impeller and didn't see any erosion, so I moved on to the next possibility.

8) As I mentioned above, when looking at the impeller, I did not see any damage whatsoever, so on to the next.

9) An idea I thought would have been the problem for sure was an electrical issue causing the plug to not receive a spark. You can test this by pulling out the plug, putting the cap back on, and holding it next to the engine block.

I've seen someone get zapped doing this, so rather than take any chances, I used some duct tape to hold it down. I've also heard that a person tried this after running a jetski hard and the gas vapor in the hull exploded bowing him back; in my case, the seat was removed and no vapors - can't be too careful, right? It did have a spark.

Test to see if spark plug is receiving a spark.

10) Cylinders go bad, so I needed to check the compression. Until recently, I had no idea how to do that! Sounded too technical, but it's actually very easy, and inexpensive - IF you buy the right tool first ;)

I ended up buying a compression tester from Auto Zone, but bought the low-end version (about $20) which works fine for older waverunners (1991), but not the newer (2008) versions. I had already used the incorrect one on my old skis, so I couldn't return it.

Turns out I needed the more enhanced unit (has a smaller plug tool for the newer modules) that cost about $42 - here is the picture:
waverunner-compression-kit

* CAUTION * - The attachment you need to connect the compression meter to the spark plug chamber screws on and then holds the plug. When you go to remove the plug, the screw becomes undone and can get stuck in the chamber! In my case, I placed some superglue on the thread, then screwed it into the disconnected attachment, and let it sit for a few minutes. It worked like a charm and the attachment came out.

* SAFETY * - I had removed all the plugs before testing compression. If you do the same and stand in front of the cylinders, you may get sprayed in the face with fuel, so make sure you are standing on the other side before testing.

compression-tool-stuck-inside-waverunner

This was a nerve racking test because if a cylinder comes back with really low compression, it may indicate that you need some VERY EXPENSIVE work done. Luckily, this was not the case for me and all cylinders tested out fine.

waverunner-compression-test

11) Next suggestion was the multi-function meter. No idea what that is and not sure it really related to my ski, so I skipped this and planned on coming back to it if nothing else worked.

SOLUTION TO WAVERUNNER LOSING POWER

12) Fuel Injectors clogged? (Yes, they were!) How was I going to check that? I had no idea where they were located, and then I find out that you need a special device to send an electric current to the injector for it to allow the cleaning solution through! No worries, here is how I built my own device using a power supply from an old wireless router and a syringe from Tractor Supply - really ;)

Parts needs to make a fuel injector cleaner for a Yamaha Waverunner

Here's what you'll need:

  • 6ml syringe - no needle. I purchased mine from Tractor Supply company (used for animals)
    Black tape
  • 12 volt power adapter (I used a AC to DC power adapter from my old router, just keep it under 12 volt DC).
  • Alligator clamps (Lowes has them)
  • On/Off button (I had a toggle switch laying around and used that)
  • Spray Can of carb cleaner with straw
  • Bucket
  • Eye protection

Power adapter for yamaha waverunner fuel injector

Take the wire and split it about half its length (not cut, but instead separate about 3 inches). Take one of the two wires, find the center and cut it. Strip the ends and connect them to your on/off button, then use some black tape to keep the two ends from touching each other. finally, find the end of the adapter, cut it off, strip the ends and attach them to the alligator clamps. You now have your device ;)

Now you need to remove your fuel injectors. It's easy, there are two bolts to remove, the fuel bar pops up, turn it a bit, then pull the fuel injectors out.

remove-fuel-bar-waverunner-fuel-injector

removing-fuel-injectors-on-waverunner

Now you'll take the injector, place the end with the rubber o-ring (washer) into the syringe tube, and tape it up so it stays in place. Attach the carb cleaner straw to the other end of the syringe and onto the carb cleaner spray nozzle. Let the end of the syringe hang into a bucket. Place the two alligator clamps onto each connect of the fuel injector, plug the AC to DC adapter into the wall. Now, press your button and then press the spray top of the carb cleaner to allow a little cleaner to flow into the injector - you'll see a spray coming out the bottom.

clean fuel injector part ii

cleaning the vx1100 deluxe waverunner fuel injectors

You don't need much to clean it out, so a few sprays and you should be fine, as long as you see a good mist coming out (there are four small holes at the bottom).

Note: I've seen some people go to town creating an elaborate system they can reuse; my system is Jimmy Rigged (get it, Jimmmy, etc. - okay, moving on...). The carb cleaner will eat through the black tape after each injector is cleaned, so you'll need to remove the tape, then tape up the next one, until you've done all four.

The Solution ended up being clogged fuel injectors and it runs like a champ now. I would like to thank Ernest T over at PWCForum.com for pointing me down the right path. It may be a simple troubleshooting process to him, but for someone that doesn't know anything about engines, it was a bright light to solving the real problem without wasting time.

How much would it have cost me at a shop?

8/20/2014 - I called Babbits (they sell and service Waverunners) and asked the service department and described my problem. First question asked was if I had learning mode on, then suggested changing plugs. They said the VX Deluxe is a great machine and probably not the fuel injector, but that they don't clean injectors, they replace them; and, if you're replacing one, probably best to replace them all.

It's $98 to diagnose the problem, $98 per hour labor, $127.01 for each fuel injector (60E-13761-10-00) and $4.37 for the O-Ring (60E-14147-00-00).

universal fuel injectorI found a couple of fuel injectors online, one being an Accel universal injector for $82.68 and a Holley universal fuel injector for $99.19.

Add that up, and we're looking at shop costs of around $820:
$98 Diagnostic
$196 Labor (guessing two hours)
$508.04 for 4 injectors
$17.48 for 4 O-Rings
-------------
$819.52 Total

Compare that to DIY parts, and you're looking at $55.47:
$0.47 6 Syringe from Tractor Supply
$0.00 Old adapter
$5.00 Carb cleaning spray
$2.50 Alligator clamps
$1.00 Black tape
$2.50 Toggle switch
$42.00 Actron CP7828A Professional Compression Tester
$2.00 Super Glue
--------------------
$55.47 Total

By doing it yourself you'll save around $764, plus, next time your Waverunner looses power and can't go past 30 MPH, you'll have all the tools to test and fix it yourself!

BTW - Tips on how to fix water entering the hull of your jet ski and a Waverunner that stalls.