• Welcome to Jetboaters.net!

    We are delighted you have found your way to the best Jet Boaters Forum on the internet! Please consider Signing Up so that you can enjoy all the features and offers on the forum. We have members with boats from all the major manufacturers including Yamaha, Seadoo, Scarab and Chaparral. We don't email you SPAM, and the site is totally non-commercial. So what's to lose? IT IS FREE!

    Membership allows you to ask questions (no matter how mundane), meet up with other jet boaters, see full images (not just thumbnails), browse the member map and qualifies you for members only discounts offered by vendors who run specials for our members only! (It also gets rid of this banner!)

    free hit counter
  • MOORING COVERS Available!

    Not sure if you noticed, but Jetboatpilot just posted that he has gotten his hands on some mooring covers.

    These things are in short supply lately, so if you seek one, you might want to check out this post!

    You can dismiss this notice by clicking the "X" in the upper right>>>>>

XR1800 4-Stroke MR1 Swap

Robb235

Jet Boat Lover
Messages
68
Reaction score
45
Points
72
Location
Chattanooga, TN
Boat Make
Yamaha
Year
2000
Boat Model
Other
Boat Length
18
Do you get voltage to the little wires in the starting relay when you turn the key? The relays have gone bad before. (checking that would confirm your suspicion that the ECU is not sending power for another reason, or if the relay is bad) Good Luck!
Just got back in town last night, plan to troubleshoot shoot this tonight if I have time.
 

Robb235

Jet Boat Lover
Messages
68
Reaction score
45
Points
72
Location
Chattanooga, TN
Boat Make
Yamaha
Year
2000
Boat Model
Other
Boat Length
18
Turned out I didn’t have the waverunner security system 100% bypassed. Now I do. I can completely get rid of the security box too. Both fuel pump primes with IGNITION ON, and both motors start and run.

Next I need to figure out my throttle cable situation.
 

Robb235

Jet Boat Lover
Messages
68
Reaction score
45
Points
72
Location
Chattanooga, TN
Boat Make
Yamaha
Year
2000
Boat Model
Other
Boat Length
18
So a little bit of bad news. After playing around with the three warning lights on the tachometer, and wiring them back to the ECU, I don’t think there is any way to get the ECU to trigger those warning lights. Even though pins 23, 24, and 25 are unused on the jetski ECU, I was hoping they’d at least still be active so that I could connect to them for the low-oil, overheat, and check engine lights on the tach.

The XR has its own stock warning lights on the dash (independent of the warning lights on the tach): two overheat lights (starboard and port), low fuel, and one low oil light intended for monitoring the 2-stroke oil tank (which is no longer there). I spliced the XR’s stock overheat lights directly into the thermoswitches of the MR1s. Tach warning lights are wired back to the outputs on the ECU. I simulated an overheat condition by disconnecting a connector from the thermoswitch and jumping the connector. As expected, the stock XR overheat light triggered immediately, but the overheat light on the tach never lit up.

So as it stands now, I don’t see any way that I can monitor for a check engine light while I’m on the water. For low oil, I can probably repurpose the XR’s warning light for low 2-stroke oil. I would have to wire it up in such a way that either motor could set off the light. I wouldn’t know which motor had the low oil condition, but at least it will alert me to knowing there’s a problem.
 
Last edited:

Robb235

Jet Boat Lover
Messages
68
Reaction score
45
Points
72
Location
Chattanooga, TN
Boat Make
Yamaha
Year
2000
Boat Model
Other
Boat Length
18
Any suggestions for new impellers? Solas has the 13/19 Concord recommended for the XR1800 on their website. Do I go with something slightly steeper to account for the alleged 5hp increase in each motor?
 

Beachbummer

Jetboaters Admiral
Messages
3,373
Reaction score
2,420
Points
282
Location
Houston TX
Boat Make
Yamaha
Year
2008
Boat Model
SX
Boat Length
23
If I was me, I'd suggest Spend no more cash until after you try it. Depending on your experience while running, you can then make the right adjustments to impeller pitch. (If applicable)

You will be breaking new ground here so making adjustments based on your performance is probably the safest bet.
 

UnorthodoxCreations

Jet Boat Addict
Messages
113
Reaction score
110
Points
92
Location
Hanover, PA
Boat Make
Yamaha
Year
2005
Boat Model
AR
Boat Length
23
I agree, try what you have before buying more. I'm guessing the new setup weighs a little more and negates the horsepower gain anyways.
 

Robb235

Jet Boat Lover
Messages
68
Reaction score
45
Points
72
Location
Chattanooga, TN
Boat Make
Yamaha
Year
2000
Boat Model
Other
Boat Length
18
So over the weekend I figured out my throttle cable situation. At least temporarily. I went with something very similar to what @UnorthodoxCreations suggested, and bought the Dorman 03336 throttle stops from AutoZone. I used the smallest 1/8" stops in the assortment. I cut the end of my throttle cables off with my Dremel, and then had to drill out slightly larger the holes in the throttle stops in order for the cable to thread through. Cut off the excess cable poking through the other end of the throttle stop, and hooked it up to the MR1 throttlebodies. Not sure that this will be a permanent solution, but now at least I could start the motor and blip the throttle. Nice to hear that sport bike sound, makes me miss my Yamaha R6 that I rode through college.

Dorman 03336.jpg

So the stock throttle levers now only use about half of the throw when hooked to the MR1 motors. I had a couple minutes of free time, so I pulled out the shifter/throttle lever assembly and I think I can move the throttle cables to different hole that is closer to the center of the rotating lever so that the throttle cable moves less. I didn't get to study it very closely, but it might be possible to move the throttle cable to a different hole that results in utilizing more (maybe all?) of the throttle throw.

Also, I ordered some additional 3-way electrical connectors so that I can extend the data ports from each engine wiring harness in the engine bay, to underneath the steering wheel. It will be nice to be able to sit in the captain's chair and be able to use the Yamaha Diagnostic System (YDS) on my laptop, instead of having to pop the engine hatch and remove the tray in order to plug YDS in. I'm going to plug into the existing connector on the wiring harness, run the wires to underneath the steering wheel, attach the mating connector, and zip-tie out of the way under the steering wheel and cap it with a blanked off connector. Will be much like the OBD2 ports in most cars under the steering wheel.

HW-S3 Connectors.jpg

Corsa Technic has been an awesome resource for finding OEM connectors for this project: Connector Kits, Terminals, Wiring, Tools | Corsa Technic
 
Top