90 hp mercury sport jet, no spark and fuel spilling out carborators

[gold1422]

I am having trouble getting spark in my regal rush with a 90 hp mercury sport jet engine. I disconected the black / yellow wire from the rev limiter and now I'm getting spark but the engine doesnt seem like it wants to start. I just bought the boat, the guy I bought it from told me it just needed a starter. So I replaced the starter and then ran into this spark problem. Shouldnt the engine still start with that black / yellow wire disconnected, does this mean the rev limiter is bad? Also when I crank it over, while getting spark, I have fuel pouring out of my carb breathers. Does this mean it may be out of time? Do I have to fix the rev limiter before I move on? It doesnt seem like a got a steal only buying the boat for $1000, now that I running into these problems?
Is it possible to flood the engine with unburnt fuel if I have the boat out of the water on a trailor?

 

[cheburashka]

Re: 90 hp mercury sport jet, no spark and fuel spilling out carborators

Sounds like it's been sitting awhile and you have multiple problems. One is the rev-limiter problem. I'm not familiar with how these work, but it seems to me that if you're careful, you could run it without a rev limiter. Does it have a tach you can use to verify RPMs?

The second problem is the fuel problem. How long has it been sitting? Long enough for the gas in the bowls to varnish up? It sounds to me like your inlet needles aren't seating, and you're getting too much gas into the cylinders. This can definitely be a problem, even when trying to run on the muffs.

Is your fuel pump mechanical or electric?

 

[Capt Ken]

Re: 90 hp mercury sport jet, no spark and fuel spilling out carborators

You can live without the rev limit box. Most do. The most common problem causing the flooding is the vents on the carbs being gummed up. There is a common hose connecting the vents on the starboard side of the carbs and connects to the airbox. Remove the hose between the carbs and make sure there isn't gum plugging up the vents.

 

[gold1422]

Re: 90 hp mercury sport jet, no spark and fuel spilling out carborators

Wow, thanks everyone, that seemed to do it. I first replaced the Rev limiter, that fixed the spark, then cleaned the vents running up the carbs and it started right up in just a few cranks. Thanks for all your help fellas. But I possibly have a few more problems. I took it out yesterday and was totally disapponted with the power/performance of this 90 hp engine. Even though my spadometer doesnt work because it may be clogged, I dont think got it going any faster than 30 mph. Is this normal speed? Is there anything I can do to boost performance or power on these little engines? B/c I do not have a manual, I dont know, is there any oil or fluid that should be changed inside with the impeller. b/c After I got it warmed up, I was going full throttle, and It would suddenly cut out or spudder speed wise, I think I heard the engine staying same RPMs, But after I slowed down and waited a few minutes, it seemed to get back to speed fine. And I repeated that a few times until I said it was time to take her back in. If there is a clutch, is it slipping, is the impeller bad? What would cause this? Any suggestions? Does any one have a manual that I could download before I go to the library and rent one?
Also do jet boats have a knocking or clicking sound to them, I dont think my engine is bad b/c motor idles smooth, its just upon acceleration, I get a little vibration it seems, or mabey its just me. I know I've asked a thousand questions but If this helps anyone other than me, this site will save people a lot of money. Thanks in advance.

 

[honestcharlie56]

Re: 90 hp mercury sport jet, no spark and fuel spilling out carborators

take the cowling off and try to isolate the knock, also it would nice if you could tell about pitch of prop, size of boat, rpms. helps us diagnose, if your motor really has a knock, you might have a bent rod.

 

[alex689]

Re: 90 hp mercury sport jet, no spark and fuel spilling out carborators

i have a sport jet that makes a little noise and vibrates a little and i've ran it for years like that w/ no problems. now ive got spark issues also.