1996 SSM Mirage with Sport Jet 120xr, plethora of issues and questions.

eightrac

Cadet
Joined
Jul 17, 2011
Messages
10
Just to start, thanks for reading this. I know its my first post but this thing is giving me a hell of a time and I need some help. As you can see in the title of the thread the boat is a '96 sugar sand marine mirage with the sport jet 120xr. Now, a little history.

I'm in the process of buying this from a friend but I wanted to make sure that it was worth purchasing. I picked up the boat heavily flooded inside (plugs in but water level below carbs) and really dirty. I drained the electrolyte from the battery, refilled and charged it to full charge. First few attempts to start were uneventful and not even a fire was heard. I pulled off the intake silencer and primed the engine to find the lower carb blowing fuel out if the inlet. I then rebuilt both carbs and synced them to eachother. I pulled the plugs, they were a little fouled but not bad so I cleaned them and reinstalled.

Now, the boat starts and runs great until you get passed about 1/2 throttle. If you go WOT or even about 3/4 throttle the engine will respond with a large amount of thrust followed by bogging down and eventually quitting if you leave the throttle in place. If you pull back to about 1/4 throttle power will be restored but you can only use about 1/2 throttle without it bogging down. I noticed a automotive style fuel filter installed between the fuel pump and carbs so I removed it and replaced the fuel line and the engine began to run a little better. I have ordered a fuel pump rebuild kit and hope to remedy this problem with it. You think this will work?

I'm getting an alarm when I hit waves about 1-2ft tall. I'm assuming this is a low oil alert since it happens only when the bottle is about 1/2 full or less. It just beeps once for a short second. Is it possible to have a loose connection under the dash or does the key cylinder have a plug on the back? If you over temp this engine, will it be alarm be intermittent like this or a constant beeping?

My steering is pretty hard and it seems to be all over the place under power yet the cable seems to have little slack. Is there anything I can do to fix this?

I'm also replacing the jet drive fluid in the morning, anything I should look out for?

Thanks ahead of time!
 

eightrac

Cadet
Joined
Jul 17, 2011
Messages
10
Re: 1996 SSM Mirage with Sport Jet 120xr, plethora of issues and questions.

Noone at all?
 

eightrac

Cadet
Joined
Jul 17, 2011
Messages
10
Re: 1996 SSM Mirage with Sport Jet 120xr, plethora of issues and questions.

Jet pump oil is changed along with the stator oil, the wear ring looked "new" to me and so did the impeller aside from about 4 very small knicks in it. I also lubricated the cup cable, steering cable and opened up the steering gearbox under the dash to find an unlubricated gearset making the steering hard. I loaded it with grease and its smooth now.

I'm fully convinced my "alarm" that is sounding is the temp siren. Seems to happen when the engine is about to bog down so I think its leaning out to the point of overheating. I'm going to not run it again until I get that fuel pump kit installed. I verified the floats have the required shape to not cover up the main jet and cause a high rpm fuel starvation problem. I am also going to disable to oil injection and start running premix to make myself feel better since I've had issues in the past with merc oil injection systems.

If anyone can think of anything else for me to check out, please let me know. I've fixed so much on this boat so far and want it to last me a long time.

One last question. I have a button for a bilge blower but dont see one, where should it have been as I see no loose wires anywhere.
 

eightrac

Cadet
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Jul 17, 2011
Messages
10
Re: 1996 SSM Mirage with Sport Jet 120xr, plethora of issues and questions.

Found my fuel pump problem.

The housing is cracked between the pots allowing one side to leak into the other and impedeing flow. I am remedying this in the morning by use of a Mr.Gasket 12S (4-7psi) electric fuel pump, Spectre 1-5.5psi fuel pressure regulator and deleting the oil injection to use pre-mix. I'll be setting the fuel pressure regulator for the max of 5.5 psi as the manual says the engine runs on pressures of 3-6psi and I cannot find a low-cost 6 psi regulator anywhere. I'll be wiring it to the ignition switch via relay and I guarantee this will remedy my fuel issues for good.
 

eightrac

Cadet
Joined
Jul 17, 2011
Messages
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Re: 1996 SSM Mirage with Sport Jet 120xr, plethora of issues and questions.

Electric fuel pump worked, no fuel pressure regulator needed but still have high rpm bogging. I think I need to check the floats again.
 

calledinsick

Petty Officer 2nd Class
Joined
Jul 13, 2010
Messages
160
Re: 1996 SSM Mirage with Sport Jet 120xr, plethora of issues and questions.

I know you cleaned the carbs but check the vent lines...they are notorious for clogging quickly and preventing the floats from functioning correctly.
 

eightrac

Cadet
Joined
Jul 17, 2011
Messages
10
Re: 1996 SSM Mirage with Sport Jet 120xr, plethora of issues and questions.

Well, after many days of troubleshooting I've found an issue with the design of the carbs. When you set the floats at the correct depth, there is not enough fuel in the bowl to sustain. I have found that if you set the floats as deep as you can, the engine will go and go and go at full throttle all day long. You just have to make sure that the needle closes before the float contacts the body of the carb. Also, my oil injection pump was very weak. I compared to to a force 120 outboard and it was definetly failing. I've gone pre-mix and all is well now. Also, by using an electric fuel pump that is turned on by the key via a 30amp relay you dont need the priming system anymore. I literally just have to bump the key to start it, every single time.
 

ranman6

Seaman Apprentice
Joined
Aug 22, 2010
Messages
46
Re: 1996 SSM Mirage with Sport Jet 120xr, plethora of issues and questions.

Could you explain to me about the float setting that you did, it sounds like it would help my problems. I have the same engine except it isn't a xr. Would that be the same carb?? Also I am courios about the fuel pump, because I have idle problems too, wonder if that would cure it?

Thanks
 

eightrac

Cadet
Joined
Jul 17, 2011
Messages
10
Re: 1996 SSM Mirage with Sport Jet 120xr, plethora of issues and questions.

OK, here's exactly what I've done to my sport jet to make it not only reliable and easy to start but 100% safer too.

1st, I have deleted the stock vacuum fuel pump. This thing is designed poorly and to be honest, its stupid. I went to my local Auto Zone and picked up a Mr. Gasket 5-7psi electric fuel pump and 30amp relay. I wired it to turn on with the key and I no longer have a need for the cold-start booster thing thats bolted next to the carbs so I removed it, plugged the fuel line that goes into the bowl and sealed up the plug with tape and rtv. You will want to remove the old stock fuel pump completely so you'll have to retain one screw to thread into a hole that passes into the block to stop an impending leak. You'll instantly notice that if you turn on the key and let the pump run for 3 seconds, you will only have to "bump" the starter to start it.

Secondly, I removed the oil injection system by clipping the two wires going to the low oil sensor leaving them disconnected and taping the ends. I disconnected the inlet oil line going into the oil injection pump and cut it about 6" long. I then diconnected the outlet oil line coming from the oil pump and filled the tube with oil and looped it so that the oil pump will just pump the same oil through itself constantly. I then removed the 3-way that is in line of the fuel pump and carb inlet and replaced the whole fuel line with one hose from the electric fuel pump to the inlet in the top of the top carb. You have to pre-mix fuel now but it gives me peace of mind since I've had the oil pump fail before on another outboard and it wasn't pretty.

Carbs...... Want problem free starting? Want to be able to run full throttle without bogging...EVER???? Do this. Remove both carbs and disassemble. You will need carb cleaner and an aircompressor with a blower attachment that has a rubber end. Use the carb cleaner and spray into every passage and blow out with compressed air with as much pressure as you can get it. Pay attention to the fuel inlet, the vent but most importantly the passage from the bowl area into the venturi. I removed tons of crud and dirt from this area with compressed air. Now, that should cure any idle problems as the fuel is now able to flow much easier throughout the carbs passages now you need to remedy that full throttle stumbling and surging. The problem here lies in the diameter of the needle and the bore of the passage it fits into. The bore is entirely too close for enough fuel to pass through to sustain when the engine is at full throttle. The manual tells you to set the float in such a way that if the carb is inverted that the float will be parallel with the body when resting against the needle. This is not nearly deep enough. At this depth, the engine will have about 3-5 seconds of full throttle operation until the bowl is drained since the needle and seat are too small to allow enough fuel into to bowl fast enough. If you look at the float with the needle stop (metal tab) towards you, you'll notice a little plastic tab that looks as if it would hit the side of the bowl (or gasket) if the float was set too deep. Take note of this as you will be making an adjustment to the float level and you won't want this tab to contact the side of the bowl (or carb gasket) before the needle is seated when the float rises with the fuel level. With the carb upside down, bend the metal tab so that the float will allow more fuel into the bowl without the plastic tab contacting the bowl. This will allow the carb bowl to fill with more fuel and remedy your surging and stumbling. Now, reassemble and reinstall the carbs. If you've done all of these modifications properly, you'll be able to turn the key to the "on" position for 3 seconds and then "bump" the key to start the engine.
 

eightrac

Cadet
Joined
Jul 17, 2011
Messages
10
Re: 1996 SSM Mirage with Sport Jet 120xr, plethora of issues and questions.

I also had starter issues where the solenoid would create a draw on the system and the starter was drawing too much power from the battery. I bought a new starter on ebay for $82 shipped and replaced my solenoid with a solenoid for a 1978 ford f150 with a 400 engine. I removed the old solenoid and rewired to allow the solenoid to be moved out of the engine compartment where the air is a bit cooler.
 

ranman6

Seaman Apprentice
Joined
Aug 22, 2010
Messages
46
Re: 1996 SSM Mirage with Sport Jet 120xr, plethora of issues and questions.

Thats some really good advice, I think I have some work to do this winter.


Thanks
 
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