Jetmate 701 swap

[Quinc]

Got this jetmate for the wife and kids. Came with a rebuilt 650 engine and wiring mostly done. I added new jettrim seat covers and a 100$ Bimini top from amazon. After having what I believe to be electric issues with the mate not letting it rev up in the water. I bought the rhaas adapter plates rather then spending money to fix the 650.

I have a stock bore 62t out of a waveraider I rebuilt with a new hotrods crank. new seals and gaskets etc, r&d head with boyesen rad valves and dual 38s.

Putting the rhaas plates together I noticed the bolts are too long for the engine mounts so I swapped them out to shorter bolts. If you dont have shorter bolts you can add a couple washers to them.


Pic of the mounts in the hull, when fitting the engine I found everything lined up best with them pushed all the way forward and in toward each other.

In the top left of the pic the 3/8" green cooling line is from fuel-line.com and fits perfectly where the stock 1/4" pisser line is. The home depot 3/8" braided line OD is too large and will not fit.


I was hoping that I could fit a lay down pipe the hull but the fit was not even close. So I will be doing the cheater pipe (bpipe manifold with stock exhaust).

For anyone that has done a 701/750/800 swap do you drill out the stock waterbox?



For the pump/impeller I wanted a skat 10/18 or hooker 10/16, but skat and impros are backordered for the next 4-6weeks so I picked up a skat 15/18. Worse case I can send it to impros and have them repitch it.


The jetmates run hot so while I had the pump out I swapped out the npt fitting for one with the largest ID I had. If she still runs too hot I will retap the pump for a 1/2 npt fitting. Or maybe dual cooling.



Next step is figure out how I want to mount the ebox and wire the switches.

 

[mikesx]

Following this one !

 

[Sanoman]

Yes,subscribed!

 

[Stavissimo]

Subscribed!

 

[Quinc]

What can go wrong will go wrong.. Was hoping to have her done today.. But ran into a few issues from stripped threads needing helicoils to the starter relay being bad..

The good is I got the ebox mounted and when jumping the solenoid I have spark. Water lines are done, exhaust hose runs back in the oem location, although the engine pushes it in a spot so hopefully its not an issue. I need to find another box that I can mount an exhaust tube around by the intake side. And I notched the bilge bracket so I could fit/run the stock bilge.

Need to fix the steering nozzle, its bent and has a large crack going through it. And the throttle cable seems to have about an inch of too much throw in it..


And once all that is done hopefully the engine cover fits without rubbing the exhaust!

It's a mess! But once I get it working/running I will clean her up.

 

[Quinc]

Re did the ebox mount using the original mount/stand. Had to notch the one side of it to fit around the rhaas mount. I also like that I can move the battery under the box at some point if I decide to turn under the seat into an ice chest. Drilled a couple holes in the oem ebox mount so I can bolt the back of the yamaha ebox to it.



and to take up the slack in the throttle cable I mounted the throttle bracket from over to under the manifold.

 

[sturat]

Save yourself the headache and run dual cooling. You can always restrict it if needed but one 1/2 and one 3/8 will be plenty. Have had real good results with TBM stuffers if you are going the stock 140 route.

Also if you can find any wraparound style pipe outside of a factory pipe, they go right in. PJS specifically.

I almost miss my old turdmate reading this thread

edit: a pjs pipe would allow you to relocate the battery to the stock waterbox location and just run a resonator or straight pipe out the back

 

[mn_reeds]

Looks like the head is all setup for dual cooling and with a factory ex manifold it would be a snap. The water flow will be limited by the through hull line so either upgrade that to a true 1/2" or add a second 3/8".

If you do have to do the cheater pipe you can port the kawi headpipe to around 43mm until it gets thin by the waterjackets. Still not quite as big as the FPP manifold but will be better. While working on the headpipe make sure to do the dry pipe mod (plug the massive stock water injection inlet, redrill to 1/8", and add a bypass on the flat boss on back).

Re waterbox: Alot of posts reference drilling 7 x 1/2" diameter holes. I'd start with 3-4 of them but make sure you position them so you could do the rest if you want.

 

[Quinc]

She's alive!!! Got the start and stop switch wired in. Used the second red wiring coming out of the ebox (waveraider) and ran it for the bilge and blower. Need to figure out how to wire in the on/off switch that takes the magnet key now. (keep the kiddos from starting it while playing around). Also need to make sure the dog house is going to fit. Hopefully have a video and gps numbers by next week.

I am going to ride it first and see how it goes before taking on the task of dual cooling and doing the dry pipe mod.

 

[Quinc]

Everything fits! No weird vibrations or issues on the hose. So fingers crossed test ride today goes well.

 

[Quinc]

first ride! with no tuning the prop slips a bit when hammering gas and top speed was 32 with 2 people in it.

 

[Quinc]

Next on the list is to add sound deadener to the dog house and see if I can quiet it down. Also think I am 1 jetsize too large on the main. going to switch from 135 to 130.

 

[Quinc]

with 130/72.5 or 75 I dont remember on pilots, and 1/2 turn out I was able to hit 33mph with two 230lb adults and a full tank. Was much more crisp but still rich. Going to try 70 pilots next and see what happens.

Also pulling a tube sucks on these things. It can pull it and get on plane quick, but It doesn't turn for sh1 t. Could not get the tube to swing out at all. Going to look for a used knee board and try that with the kids next.

 

[Quinc]

Had my dad in the back seat with the temp gun and the water coming out of the head/pisser was hot enough to burn your hand. Cylinder temps where around 130-145 while idling/cruising and only 115-119 while running at full throttle. Also the front cylinder was running about 10 degrees hotter than the rear (feeling the cylinder not the head) so I added a 2.3 seat in the water line going from back of head to exhaust headpipe to try and force more water to the front. Adding the seat made no change to the exhaust temps. or max mph.

On another note the low speed prop spin went away after i pulled the weeds out of the intake grate.

 

[Stavissimo]

first ride! with no tuning the prop slips a bit when hammering gas and top speed was 32 with 2 people in it.

My god, stop it! I can’t buy anymore jetskis!

 

[Harbor]

Had my dad in the back seat with the temp gun and the water coming out of the head/pisser was hot enough to burn your hand. Cylinder temps where around 130-145 while idling/cruising and only 115-119 while running at full throttle. Also the front cylinder was running about 10 degrees hotter than the rear (feeling the cylinder not the head) so I added a 2.3 seat in the water line going from back of head to exhaust headpipe to try and force more water to the front. Adding the seat made no change to the exhaust temps. or max mph.

On another note the low speed prop spin went away after i pulled the weeds out of the intake grate.

View attachment 415164

Dang that’s a sweet set up!

I had the uneven cooling temp on my ski too, tried the staggered size restricters too and that did not even it out. It turned out to be uneven fuel metering thru each carb, via the mixture screws… The method I used to isolate it was to rotate the carbs on the speed plate 180 degrees, rear carb now on front cylinder and front cylinder carb went to rear cylinder.. And what do you know, The cylinder temp difference followed the carbs… learned first hand that 3/4 turns out may not equal the same amount of fuel for each carb on one ski…. In my case the hotter cylinder was the correct fueling carbs low speed screw circuit, the colder cylinder was getting more fuel thru the low screw and cooling the cylinder..

Not saying you have that, just sharing what I had, and it took me some time to figure this out..

 

[Quinc]

Dang that’s a sweet set up!

I had the uneven cooling temp on my ski too, tried the staggered size restricters too and that did not even it out. It turned out to be uneven fuel metering thru each carb, via the mixture screws… The method I used to isolate it was to rotate the carbs on the speed plate 180 degrees, rear carb now on front cylinder and front cylinder carb went to rear cylinder.. And what do you know, The cylinder temp difference followed the carbs… learned first hand that 3/4 turns out may not equal the same amount of fuel for each carb on one ski…. In my case the hotter cylinder was the correct fueling carbs low speed screw circuit, the colder cylinder was getting more fuel thru the low screw and cooling the cylinder..

Not saying you have that, just sharing what I had, and it took me some time to figure this out..

Good to know! Going to take off the carbs and make sure no junk got into the pilot jet. Thank you sir for continuing to skool me!

 

[Quinc]

7mil Marine closed foam Sound deadener added to the dog house. Surprised by how much quieter it is on the trailer. Hopefully it makes a noticable difference on the water too.

 

[Quinc]

Took her out and went through two tanks of gas pulling a tube and kneeboard! Sound deadener helped a ton but going to add some more and try and get her even more quiet.

Biggest help for pulling the tube was a pull harness with a pulley and the orb/tube thing that goes between the boat and the tube to keep the rope out of the water. Was finally able to swing the tube back and forth over the wake with two adults on the tube and 2 adults and 2 kids in the mate.

Now the question is can I add one of these suction cup wake tabs and will it be enough to create a decent wake.

 

[Quinc]

Still chasing the off idle vibration. New dampener made it slightly worse.
Almost like the engine is at the slightest angle. I loosened all the bolts holding the engine mounts and rhaas plates and I still just cant get it perfect. So going to have to start drilling next..
/ Engine
I midshaft

I also noticed this bolt was rubbing into the hull so I ground it down, but that it didn't make any difference.

So now I am tired of this thing and thinking about selling it.