1994 Sea Rayder Mercury Sport Jet 90 Running motor with flush kit???????? HELP

bedwards36426

Petty Officer 3rd Class
Joined
Jan 30, 2012
Messages
76
Just bought a 94 sea rayder. Sport Jet 90. The guy I bought it from hooked the water up to the flush kit on top the motor by the thermostat to run when I bought it. I've got it home and ran the boat same place he hooked water source up. But the motor seems to be running hot. I don't think this is correct but don't know for sure. I have a Mercury Manual it shows a place on the starboard side of the motor to hook to and flush the pump but says nothing about running motor. Also there is no water coming from the tell tale. But I don't even know if that's what it's for. Or if it even has a tell tale. If someone with experience with running a sport jet out of water will please explain or help me to understand the proper procedure for this. Like I said it wants to run hot. Haven't put in water yet so really don't know if I have another problem like debris or something.
 

calledinsick

Petty Officer 2nd Class
Joined
Jul 13, 2010
Messages
160
Re: 1994 Sea Rayder Mercury Sport Jet 90 Running motor with flush kit???????? HELP

Don't run the SportJet out of the water without a water supply! I made a hose connection from parts at Home Depot:
sj8.jpg


Water pressure needs to be low...more pressure than what is shown here (holding hose out in front of you) will fill the cylinders and create hydrolock:
sj9.jpg


The connection is at the rear of the Jet drive in the engine compartment (below the spark plugs and on the top of the jet drive):
sj13.jpg


Hope this helps!
 

bedwards36426

Petty Officer 3rd Class
Joined
Jan 30, 2012
Messages
76
Re: 1994 Sea Rayder Mercury Sport Jet 90 Running motor with flush kit???????? HELP

Don't run the SportJet out of the water without a water supply! I made a hose connection from parts at Home Depot:
sj8.jpg


Water pressure needs to be low...more pressure than what is shown here (holding hose out in front of you) will fill the cylinders and create hydrolock:
sj9.jpg


The connection is at the rear of the Jet drive in the engine compartment (below the spark plugs and on the top of the jet drive):
sj13.jpg


Hope this helps!


Yes Sir this sure helps me. I have been doing this wrong. which means the previous owner i bought the boat from had been as well. I still have a couple of questions for you if you dont mind. The connection on the pump you can run your motor on the trailer with this connection on right??? I ran the boat a couple of times with the other connection running water to it. i noticed the motor seemed to be running hot but not hot enough to do any damage. Seems as though I got really lucky. To run the boat off the connection you have pictured do you turn the water on first and then start the motor, or start motor then water, or it does it matter??? I really dont want to mess anything up. Just got the boat about 4 weeks ago been doing little odd and ends with the motor that it needed. But i really need to run it at the house without taking a half hour away to the closest lake. Will you let me know the steps water first then motor or motor first then water. It will be a couple more weeks before i go test kit out in the lake, and i would like to run it at the house some before then. Also does your boat have a tell tale or (pee) hole???? Mine does but the water line runs by the motor up under the seat, so dont know where its connected? Dont know if these early sport jets were equipped with these?? Would like to know what that ones on the back of my boat for. Thanks for taking the time to post those pics, and thanks in advance for anymore help you can give me!
 

calledinsick

Petty Officer 2nd Class
Joined
Jul 13, 2010
Messages
160
Re: 1994 Sea Rayder Mercury Sport Jet 90 Running motor with flush kit???????? HELP

You need to have the water running first with no more pressure than what is shown in the pic (PWC's are a different setup)! The way the SJ is set up, unspent fuel (from cranking) flows out of the engine with the exhaust and can ignite in the exhaust/pump area...a loud 'BOOM' and your ride plate is blown/bent! If you've had a loud backfire make sure to check the ride plate under the boat (holds the intake grate). If the edges aren't flush with the bottom of the boat you have more things to work on. Having the water on before cranking carries the unspent fuel away. No tell-tale on mine.
 

bedwards36426

Petty Officer 3rd Class
Joined
Jan 30, 2012
Messages
76
Re: 1994 Sea Rayder Mercury Sport Jet 90 Running motor with flush kit???????? HELP

You need to have the water running first with no more pressure than what is shown in the pic (PWC's are a different setup)! The way the SJ is set up, unspent fuel (from cranking) flows out of the engine with the exhaust and can ignite in the exhaust/pump area...a loud 'BOOM' and your ride plate is blown/bent! If you've had a loud backfire make sure to check the ride plate under the boat (holds the intake grate). If the edges aren't flush with the bottom of the boat you have more things to work on. Having the water on before cranking carries the unspent fuel away. No tell-tale on mine.


Thanks Buddy you helped me understand what to do now. I heard no loud boom but I'll check anyways just to be safe. I may have said it but I do have the factory fitting like the one you have. So now I know the proper way to cool the motor. I really appreciate it. The so called consumer flush kit on top by the thermostat is used to wash out intake after salt water use I guess? I tried to post pic off my IPhone wrong format, at work really don't have time to change the format of them now. I wanted to post pics off that tell tale of the back of my boat. It has 3/4" line coming from it, but like I said runs underneath the seats somewhere have no clue. As long as its running at optimum temp I don't care what it's for. Look calledinsick thank you for giving me a better understanding of how this works. Hope you didn't have to callinsick to help me out! HA!!!
 
Joined
Apr 12, 2012
Messages
12
Re: 1994 Sea Rayder Mercury Sport Jet 90 Running motor with flush kit???????? HELP

Can a bend ride plate be straightend? Also if it is sticking out past the bottom of the hull will it cause a problem with thrust when you are running the boat? Sorry to post here can't seem to find out how to post a new thread.
 

venxxxxx

Seaman
Joined
Apr 25, 2011
Messages
55
Re: 1994 Sea Rayder Mercury Sport Jet 90 Running motor with flush kit???????? HELP

callinsick... question for you. Anyway to make the hose longer/ an extension maybe...from the intake hose to the connector. Because on my boat, its way in the back and a pain in the arse to screw/unscrew it.
 

Drox

Recruit
Joined
May 10, 2012
Messages
1
Re: 1994 Sea Rayder Mercury Sport Jet 90 Running motor with flush kit???????? HELP

The ride plate can be straightened if slightly bent. If the ride plate is not flush and seated properly, the jet will cavitate (suck air) and you will be frustrated with performance. Mine was slightly loose, yet it appeared to be flush with the bottom. Although, it randomly lost power at speed causing me to hunt down the cause... I finally guessed correctly that it was the ride plate.

I was missing a couple of screws in the ride plate and found that someone had replaced some of the screws improperly (with the wrong thread). It took me awhile to find the right combination of screws to get everything tight... but once it was tight - the problem was gone.

A side note - I had a problem with the RPM limiter that caused a similar loss of power at high speed - but it is easy to tell the difference between the cavitation and the loss of power due to the RPM Limiter. (Limiter sounds like the engine is missing on one cylinder).

Can a bend ride plate be straightend? Also if it is sticking out past the bottom of the hull will it cause a problem with thrust when you are running the boat? Sorry to post here can't seem to find out how to post a new thread.
 

CharlieFoxx

Cadet
Joined
Jan 9, 2010
Messages
9
Re: 1994 Sea Rayder Mercury Sport Jet 90 Running motor with flush kit???????? HELP

What are the dimensions of that part pictured above?
 

tednv

Seaman
Joined
Aug 6, 2012
Messages
60
Re: 1994 Sea Rayder Mercury Sport Jet 90 Running motor with flush kit???????? HELP

The one I use works a lot better (I ended up buying a few of them to see which one works best)

I present to you Ted's Quickbrown Dealer Flush Kit PN# 000012314 can be purchased at any home depot or lowes for about $3. It'll be in the plumbing section with all the other brass fittings

photo 2.jpgphoto 1.jpgphoto 3.jpg

It's a Male 1" and a 3/4" flare fitting. The 1" end hooks up to a water hose (no need for clamps/adapters, just plain ol' water hose) The 3/4" flare goes onto the hose that goes to the exhaust. If you don't use a flare, it'll leak out the back of the fitting so if you don't a bunch of water everywhere, get the flare end to match what's on your engine

Note: Start out with a trickle, then add a little more to get a nice stream coming off the back of the ride plate. You don't want to give it too much or you'll blow the exhaust gasket. This DOES NOT mean you can run WOT, only idle with maybe a few pumps to 1/2 to make sure it's running well

What are the dimensions of that part pictured above?
 

dabestkid37

Recruit
Joined
Jul 16, 2013
Messages
1
Re: 1994 Sea Rayder Mercury Sport Jet 90 Running motor with flush kit???????? HELP

The ride plate can be straightened if slightly bent. If the ride plate is not flush and seated properly, the jet will cavitate (suck air) and you will be frustrated with performance. Mine was slightly loose, yet it appeared to be flush with the bottom. Although, it randomly lost power at speed causing me to hunt down the cause... I finally guessed correctly that it was the ride plate.

I was missing a couple of screws in the ride plate and found that someone had replaced some of the screws improperly (with the wrong thread). It took me awhile to find the right combination of screws to get everything tight... but once it was tight - the problem was gone.

A side note - I had a problem with the RPM limiter that caused a similar loss of power at high speed - but it is easy to tell the difference between the cavitation and the loss of power due to the RPM Limiter. (Limiter sounds like the engine is missing on one cylinder).

im having the cavitation issue but have taken the ride plate off and reseated it is still doing the same thing out on the water sounds like the rear end of the boat comes out of the water but the only way to make it stop is to slow way down any answers?
 
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