2008 WaveRunner troubles

[Pinhacker71]

Any ideas as to what is happening?
Last week I bought 2 2008 WaveRunners. A VX deluxe and VX cruiser. Each with around 140 hrs. Took them out and ran good for 2 hours. Brought home and changed plugs, oil, and filter. Pulled out cruiser air filter because oil was high on dipstick. Filter was soaked so I tossed it and did not replace. Decided to also remove ribbon at this time on cruiser. Had to pry it out. Good film of oil behind ribbon and I removed a few metal flakes from the ribbon. Took a good look and feel and did not see any other pieces. Put everything back together and put to river. Cruiser definitely had more power and went about 3 mph faster 52 on dash. After about 10 min power dropped to 30 mph with no oomph. Drove back to dock. Pulled plugs and all were pretty black for 10-15 minutes on them. Replaced plugs and went back out. 37 mph on dash but still a dog. Pulled plugs and all but second from stern look good. Pulled pump and nothing there. Waiting on adapter to check compression. Did I screw something up?pic is of plugs after 20 min of driving at full throttle, 35-37 mph.

 

[Seadeals]

Don’t think you screwed anything up, just the way it already is. No.3 is usually the problem child cylinder. You definitely need to check compression on all but 3 looks to have an issue going on (exhaust valve sticking) with that much oil it starts to have trouble firing after the plug fouls. If you suspect ignition is intermittent, you could swap coils and start with clean plugs again to see if the plug on the original coil gets dirty (I think that is unlikely).

 

[Seadeals]

Also, aren’t those plugs supposed to be cr9eb?

 

[Pinhacker71]

Yes. I was told to try these cr8eb. Someone’s said they may hold up better over at greenhulk. Apparently can handle higher temps. Don’t know if that is true.

 

[boudin]

I know a lot of folks do the 'ribbon delete', but that's your flame arrestor. I never really liked the idea of deleting my flame arrestor for 1-2mph. Did you use a kit? Does the ski idle correctly now? If you don't use a kit and use the PVC pipe technique, it's easy to introduce an air leak.

I would change the plugs back to cr9eb's, double check the oil level when warm, and also get your injectors cleaned and spray tested. I use injectorrx.com. Cheap and quick turn around. Be sure to ask for a before/after test. And as others have said, do a compression test.

-Greg

 

[Jgorm]

It's either a bad oil leak, injector is dumping way too much fuel, or the compression is so bad it won't fire. As mentioned, change back to the stock heat range plugs. Check oil level and smell oil for gasoline contamination.

 

[Pinhacker71]

I will do come compression test tomorrow and report back. Hoping it is ok.

 

[swatski]

I didn't think ribbon delete was helping anything in MR-1s...
It is a must-do in N/A 1.8.

--

 

[Pinhacker71]

Idk. Just saw a guy on YouTube do it and thought why not. Probably just getting rid of the oil soaked from later would have been enough.

 

[Jgorm]

It's this the mr1? If so i got 10 bucks it's the exhaust valves leaking or stuck on #3.

 

[Pinhacker71]

Yes mr1. Did compression test. 160-170 on all cylinders. I know that is good but question is what is the problem now?

 

[Scottintexas]

It's either a bad oil leak, injector is dumping way too much fuel, or the compression is so bad it won't fire. As mentioned, change back to the stock heat range plugs. Check oil level and smell oil for gasoline contamination.

I think you change your oil to make sure that's ok and wonder that injector is dumping fuel and get your injectors clean /tested maybe swap the coils to be sure your getting spark

do you have a yds?

 

[Pinhacker71]

I’ve checked spark. All coils fire. Can I switch out injectors and see if that solves problem. Take one off other Waverunner and swap them? I do not have yds. No codes showing when I check on display.

 

[Pinhacker71]

I also added a full bottle of seafoam to 1/2 tank before I ran it. Could that have screwed up something? Maybe knocked something loose? Idk.

 

[Pinhacker71]

Switched up injectors and placed new plugs. Ran on hose for 30 min. Plugs look ok. Not sure if failure happens under load. Will take out to river Sunday.

 

[Pinhacker71]

Update. Still fouling same plug. Not nearly as bad this time. Plug sparks when I test it but it looks fouled. Checked oil level and slightly high. Removed 1/2 quart. Plug doesn’t look oily and definitely not wet. Compression is good son all cylinders. Plug sparks in ignition coil but I now wonder if coil could be bad just enough to cause rapid fouling of plug. I switched fuel injectors around and that didn’t do anything. Next step is to swap a coil from my other ski and see if that makes a difference. If this doesn’t work I guess off to the mechanic for half the summer. I would think since compression is same on all cylinders shouldn’t be a major issue? Never get up to full rpms. Seems to never have power to that cylinder.

 

[boudin]

I'd recommend you move this thread over to greenhulk.net, in the Yamaha 4-stroke Performance section. Lots of experienced folks over there.

-Greg

 

[Jgorm]

If you swapped the injector and it didn't follow that rules those out. It could be the coil, but if it's sparking, then it's unlikely (but worth ruling out). If it's not that, it's probably a bad valve seal leaking in oil, or a sticky exhaust valve that works sometimes. I think both of my waverunner with the mr1 do that. It's like an in off switch where i gain 5mph and 1000 rpms. Very noticeable. It can't really be any other sensor because it's specific to one cylinder.

 

[Neutron]

A compression test can fool you. A real test is a cylinder leak down test. If there is a problem area it will narrow it down

 

[Pinhacker71]

Guy at greenhulk also suggested could be ecu? I think I’ll swap the ecu from other one and see what happens.