1995 Sierra Viper Question s

[S.S. Talladege]

Hello everyone.

So from what I can tell is I have a 1995 Sierra Viper jet boat titled as a Mirrocraft oped bow jet. I can't seem to find ANY information on it. Looking for an owners manual mainly but would like any other information to let me know common issues, experience, ECT.

The boat has a Mercury Sport Jet 120xr as the powerhouse. The first day we took it out it would sputter whenever you pushed it over 3/4 throttle. Put a new battery in it some fresh gas and day two it was running like a top! You'd pin it and it would stand up, level out and glide across the water around 40mph (guessing speedo is broke but it was hauling)!... for about an hour of off and on fun. After about an hour when I'd pin it the engine would rev up, the front of the boat would lift and nothing... It was like it was stuck aimed at the sky going nowhere fast (still moving forward but probably closer to 15mph). Nothing changed that I can tell. I don't see a trim control. Any help would be greatly appreciated. This is my first boat, it was a gift from my grandpa.

 

[tdonoughue]

Sounds like you have something blocking the jet intake. Check that and to see if there is anything wrapped around the intake grates or anything that might cause cavitation.

 

[S.S. Talladege]

Sounds like you have something blocking the jet intake. Check that and to see if there is anything wrapped around the intake grates or anything that might cause cavitation.

So I climbed under the boat and I don't seem to see anything covering the intake or past the grate.

 

[tdonoughue]

Ok. Next: When you move the throttle forward, does the gate over the jet in the back lift?

Note: sometimes whatever was on the grate falls off when you are taking the boat off the water... You may find next time you put it in it is 'magically' better.

 

[S.S. Talladege]

Ok. Next: When you move the throttle forward, does the gate over the jet in the back lift?

Note: sometimes whatever was on the grate falls off when you are taking the boat off the water... You may find next time you put it in it is 'magically' better.

So the gate moves with the throttle. I took apart the rear assembly and found nothing lodged in there. Looks pretty corroded. Do you notice anything?

 

[Dixie Highway]

Does the boat take on water? Sounds to me like after some time running water accumulated in the bilge, and when you try to plane it moves aft causing what you describe. When my boat is heavily loaded it will take quite a bit longer to plane, sometimes feels like it will never get there.

 

[S.S. Talladege]

Does the boat take on water? Sounds to me like after some time running water accumulated in the bilge, and when you try to plane it moves aft causing what you describe. When my boat is heavily loaded it will take quite a bit longer to plane, sometimes feels like it will never get there.

When I pulled the plugs I feel like it drain a lot but I'm also not sure what's considered a lot. I do know the bilge pump isn't working. Trying to figure out where the wiring is messed up or if it's the pump or auto switch. Same with the blower motor. I will try to get this fixed before Saturday and see if that helps. I think this makes the most sense so far. Thank you for your input.

 

[tdonoughue]

Yes, I don't see anything really problematic on the pump. Like you said, some corrosion, but nothing that should be that fatal.

I like @Dixie Highway 's idea. When you put it back in, does it start off going as normal again (before it fills up)?

 

[Dixie Highway]

You could easily test that by putting in the plug and filling the bilge with a garden hose. If you see drips or leaks anywhere that's where water is getting in.

 

[mkemp]

So the gate moves with the throttle. I took apart the rear assembly and found nothing lodged in there. Looks pretty corroded. Do you notice anything?
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The jet sleeve may be worn? I have the same boat after two years I have finally got it dialed in. last summer mine was doing something similar after replacing the jet drive, I rebuilt the the fuel pump, the diaphragm had a hole, thing runs like a top now.