My opinion of the 2021 version of the N A 1800 engines and info on the new Yamaha hull design on the FX pwc models

[Cobra Jet Steering LLC]

Keeping in mind I have P W C's not boats, my last 2 were 2014 models with the 1800 NA engines, aside having a chain hatch on one of them and Yamaha covered under my warranty I put 870 hours on these , the pumps are still original never been rebuilt but I did add gear lube to the grease a couple years ago at 650 hours. I did change the pump housings over to the plastic liners around that time also. The impellers are all original as well as the drive shaft and all but one motor mount. The engines run fine they usually topped out between 55 and 58 mph the acceleration was ok, obviously not like the super charged versions but they do not need premium fuel either. I have owned a super charged Yamaha and a Crapasacki that I still will never waste another second on one of those. So recently I purchased a couple of new 2021 Yamaha skies one from barneys and one from Cycle Springs a side note locating new FX models is not easy and I needed to get 2 before the end of the year, Neil at cycle springs was very helpful in that endeavor.
Now keep in mind the weather has been poor to say the least and having 2 new skies to break in is time consuming as I am one of those people who break in the ski very carefully and slowly, probably why they last so long considering how hard I drive them.

My first impression of the new skies this is important because I have 2 and getting the same results from both makes my findings credible in my opinion.
I start out just idling and gradually put the engine in no wake mode, I run that speed for about 30 minutes so it gets boring to say the least.
Eventually I get out of no wake mode and start to very gradually increase the speed a couple of M P H at a time and stay there about 15 minutes what a surprise when I reached 15 mph and the ski violently rocked side to side it continued to do that until I either reduced the speed or increased the speed to about 20 NEVER in my life did I experience anything like that on any ski I owned, I played with the trim and found raising it up a bit would reduce that effect but not get rid of it. This was totally unacceptable in my mind. I found the same exact issues with both skies so I readjusted the trim to a better location on both and went out on a second day to continue the break in process, now I also posted on some p w c sites to see if anyone else had this problem and I learned it was a common issue along with the wet ride issue I experienced on these hulls. SO for the record my skies already had my steering added and my Jeff cruise and a few other things like my custom intake grate. and all the tricks I do to the engine and intermediate bearings never seize and white lithium grease on the engines and electrical and I had a hell of a time inventing a funnel that would work around that huge vent they placed in the filler tube without spilling fuel out. So I had some time invested in this set of skies. So back on the water and I get out riding around 25 mph for the day using the cruise control and bumping the speed up and down etc for a day with a few increases to 40mph and then back down again.
But the chine walk is just not going away so I call on the inventor in me and I ponder a solution and then I decide the hell with it and modify both skies go for broke or go home.
Next I bring out the skies and my girlfriend she has never driven them she has only seen them in the front yard. SO I take the one she is going to operate and warm it up for her this is a ritual I always follow slow warm up before going any plaining speeds. then I warm up the one I am going to drive. I explain the process to her that we will not be opening these up for a few hours and we will be cruising around 30 to 35 most of the time. I then have her get on with me so I can explain the E series because she has only driven the 2014 models. Once she feels comfortable with the differences we go riding around in the damn fog freezing , well she was freezing I was just a bit chilled. Now the good part I had warned her about the chine walk just in case my mods did not solve the problem, well it was so impressive that I just could not believe how big a difference the mode made and the ski hit 60 mph so damn fast I was thinking it was close to the acceleration of the supercharged skies I had previously.
I told her to go do some maneuvers and tell me what she thought and all I saw was smiles and thumbs' up she would rather ride on the back than drive and she drove it all day long 5 hours, so here is the other thing that totally amazed me about this engine design, they obviously made some changes because every time I ride them where my old skies would burn through 5 gallons of fuel an hour religiously year after year, these engines burn half the fuel I went through 9 gallons of fuel between the 2 skies for the entire day. So the fuel economy acceleration and top speed was impressive I put her on the back hit 60 mph in a flash out of the hole. And no more chine walk. great day on the water.

 

[WREKS]

@Cobra Jet Steering LLC How do you determine when it is necessary to change a motor mount?

 

[Cobra Jet Steering LLC]

When you do the intermediate bearing you have to move the engine and you see that the motor mount is broken when you go to unbolt it.

 

[Cobra Jet Steering LLC]

If you want to check them just rock the engine side to side and see if one allows the engine to move more than it should

 

[WREKS]

@Cobra Jet Steering LLC Thanks ?

 

[TimW451]

What was the mod that got rid of the chine walk?

 

[Cobra Jet Steering LLC]

I put water skies on my steering fins haaa just kidding that would be just so silly.
I am currently in the process of deciding if I want to patent this and if I want to license it so for that reason I am not discussing any of the details currently.
However I Will brag on it , with the steering I made for this hull and the mystery mod I have just fallen in love with, these new skies where as prior to this last mod I was thinking I made a huge mistake and if others have this new hull design and do not like how it violently rocks side to side between 15 and 20 m p h you can probably understand what I mean.
Keep in mind I do a lot of stunts with skies and one in particular is standing on the seat with my hands in the air and even towing tubes doing that so when the hull showed it's lack of stability I was really disappointed. NOT ANY MORE!!! I love driving them now and combined with the steering makes it so maneuverable and no I am not pushing the steering because I just don't have the time to handle all the boat orders and make custom parts as well. All my P W C parts are custom hand made parts.

 

[swatski]

Kudos on improving on Yamaha rides, they do have a tendency to make their hull redesigns a little wonky, some loose speed, or now they wobble?

Regarding the fuel consumption though, I'm curious, is it the engine mods, or the hull mods that contribute the to better fuel economy? I would think one would need to swap the old and new engine and hull to test it rigorously, no? Otherwise, it maybe hard to tell. What would they do to the engines? run them less rich, maybe, but that wouldn;t save a whole lot of fuel.

--

 

[TimW451]

If the chine walk is a systemic issue, and not induced by other mods, I’d say you have something marketable and with your experience patenting you should move forward on that. Licensing sounds like a better option than self production. Good luck with your decision.

 

[Cobra Jet Steering LLC]

My research shows it is a common issue with those hulls. As for the fuel consumption - it isn't just a little difference it is a serious difference I am very impressed .
I need to get the cover off and look in the computer for the fuel consumption report , I believe it keeps track of all that.

 

[rpm242LS]

I'm a little confused, did they change the hull design from model years 2020 to 2021? I did not think they did but could be wrong. I have a 2020 FX cruiser with the na 1.8 engine. I put over 70 hrs on the ski last year and I do not have any of the issues you mention at the lower speeds (at any speeds actually) it is very stable and turns like it's on rails.

 

[Cobra Jet Steering LLC]

Facebook Groups here is the discussion I have on a Yamaha wave runner site seems like a common occurrence and a person is cutting the ride plates to fix it but if you don't hold your speed in the area of 15 to 20 mph you won't notice it so next time out try maintaining a speed of 15 to 20, and see if it happens I believe you have the same hull . next time out I am going to see what top end I get since I hit 60 with 2 people and felt like It had more and the fuel tank was FULL. I just did not want to hold it at W O T for more than a few seconds.

 

[rpm242LS]

I'll have to try that with the 15 to 20mph. I'm sure I have spent a lot of time in that throttle range maybe just never noticed. I wonder if weight plays a part too, I'm 220 lbs.

At WOT I get just over 62 Mph with me alone, with two ppl I may just hit 60 but not over that. But that's with about 400lbs ppl weight on it. It's completely stock.

This year I may pick up the seedoo with the ACE 300 engine in it. I know that one will be fast and the hull design seems to be with a slightly more pronounced V shape that should handle really well. I'm just not sure about the engine longevity, the Yamaha 1.8s I know will last if I take care of it.

 

[Cobra Jet Steering LLC]

I am not really into FAST driving, I like cruising and obviously trick driving I loved wave jumping but my Hip won't allow me to do any more of that. Most important to me is reliability, I had some sea doo's and I had a lot of pump issues I actually carried a back up pump in my van Had to change it out at the ramp a few times . "still have it as a matter of fact"
Electrical problems were common as well as the carbon seal issues and exhaust leak problems, plus motor mount failures.
I stopped buying those.
The only real issue I have with Yamaha is the weak Nano hulls when they fail I fix them, I am really hoping they addressed that issue on these 2021 models since they changed the design.
So far Yamaha pumps have lasted me the longest.
I actually purchased a rebuild kit for these pumps a couple years ago just to have on hand it is still in the unopened box never needed it.
Only thing I have had to do in that respect is intermediate bearings at 650 hours and the pump liner sections and I change those to after market replaceable nylon liner sections and I have never had any issues with that. But I do add gear lube to the pumps in with the grease and now I do that with the intermediate bearings as well. Did these 2 new ones on day one so I am curious to see how long they last, looks like Barneys pumped grease in theirs but Cycle springs did not so I will see what one lasts longer etc. I never grease those as it causes damage to the rubber and the seals. my advice is to add a Jeff cruise to your ski it is great for cruising and with the cruise assist it is even better since you can set the range you want plus bump the up or down button as you go along and you can stand up at 50 and drive by leaning without using your hands I basically do most of my driving standing hands free.

 

[rpm242LS]

I'm not necessarily into fast driving either but my opinion has always been a larger more powerful engine doesn't need to work as hard for cruising speeds and therefore a longevity theoretically should be better. That's why I was looking at the ACE 300s.

Not trying to hijack the threat at all but what you mentioned about reliability is also my concern with a rotax engine and pump. We're also looking to get a newer larger boat and a Scarab 285 is on the short list but I have concerns similar to what you mentioned above.

 

[Cobra Jet Steering LLC]

I get what you are saying about HP but some thing in me " after owning 2 supercharges skies is forgetaboutit, more hp meant more issues less room to work and a huge fuel bill I hate wasting money I am quite happy with the 180 hp it tows 2 tubes with 5 people in them at the same time what else could you want ? And that was the 2014 skies I can't wait to terrorize my grand children with these new skies .

It never gets old.

 

[Cobra Jet Steering LLC]

Took the new skies out to test the stability and maneuverability of the latest mods now that they are broken in , but forgot to bring the camera , next best thing I had my girl friend try to shoot them on her phone but it was difficult for to follow me however you will get the idea the 2 new Jeff skies playing even driving while standing on the seat and turning the handlebars from the top of the seat plus watering the plants for some reason I can not post the phone videos try as I might so I put them on the cobra jet steering facebook page. Cobra jet steering