94' 90hp Merc. Sport Jet That Will Not Start

I recently purchases a Reagle Rush jet boat with a 90hp Mercury Sport Jet, before I bought it the previous owner started it up on 3 separate occasions. I bought it on a Friday, took it home and didn't touch it till I put it in the water on the following Wednesday. Long story short, I drained the battery two hours later trying to get it started. It would just crank and crank all day but never fire or even sound like it wanted to fire. I should mention that not once did I ever smell any gas due to flooding. When I took it home I tested the electrical and it has great spark on all three plugs and all the coils are good. It has a stage 2 fuel pump but dose not have a bulb primer, I read in a repair manual that there should be so I went and put one in. I can get the pump to get the gas to the carbs but again I can hold the throttle wide open and it will not fire and you cannot smell any gas. I started to think that maybe he was spraying starting fluid in the intake to get it running to sell it so I bought some fluid and got it started for a second but as soon as you give it gas it would cut out. I know it runs I just cant figure out if the fuel pump is bad or the carb needles are stuck or its something I'm just looking past. If anyone has any suggestions for this I would be more than open to hear it, I'm pulling my hair out cause I know it starts.

Re: 94' 90hp Merc. Sport Jet That Will Not Start

Are you using the primer button on the controls? On my 84 merc 90hp inline 6 I have to set the throttle to 1/3 or so in neutral, turn the key to the run position, then push the key inward 4 times to give it 4 shots of primer fuel. Then it will start no problem. If I don't prime it, I could probably drain the battery just like you. My 81 merc 175 has an electric choke flapper door instead of an electric primer, so to start that one I have to again set the throttle to around 1/3 in neutral and have to hold the choke button down as I crank the engine over. And yes on both of mine I have the fuel primer bulb squeeze it until it gets hard.

Re: 94' 90hp Merc. Sport Jet That Will Not Start

I have tried both ways....trying to start it just using the choke on the controls and with the throttle open. I think my problem is somehow I'm just not getting gas usually if you leave the throttle open it will flood and you can smell gas. I am never able to smell gas.

Re: 94' 90hp Merc. Sport Jet That Will Not Start

Are you using the choke/primer like I described? You won't flood it by cranking with the throttle wide open. There's little fuel delivery during dry cranking, that's why it doesn't start unless you give it a few shots of primer with the button on the controls. If you have spark and compression, it will at least try to fire if it gets some fuel flow. I'm still thinking you're not using your electric primer properly or it's not working right.

Re: 94' 90hp Merc. Sport Jet That Will Not Start

Sounds like you're not getting fuel. Have you tried taking the fuel line off before it goes to the first carb and cranking the motor? You should get a steady stream and no pulsing action. If you get pulsing or no fuel, check the fuel pump out further.

Re: 94' 90hp Merc. Sport Jet That Will Not Start

jmff38 said:

Sounds like you're not getting fuel. Have you tried taking the fuel line off before it goes to the first carb and cranking the motor? You should get a steady stream and no pulsing action. If you get pulsing or no fuel, check the fuel pump out further.

Click to expand...

I have checked the lines going into the carb and they are all clean and gas flows through them freely. I have also rebuilt the fuel pump when I first started working on it and that is working well also.