Lower noise and vibration

[bluetopper]

I have a 2001 Utopia 210 hp sport jet. Just noticing some intermittent slight banging, not bad, along with some vibration when it does it. Like about every 5-8 seconds. not all the time. Sounds and feels like it's coming from the lower pump assembly. Also my engine will only turn 2700 rpm's in the water. Out of the water with a water hose it will rev up as normal.
Also......I have a brand new powerhead (engine) with the auto oil injection taken off. It has 2 hours on it is all.
A lot going on here I know.

 

[Tim75]

I have a 2001 Utopia 210 hp sport jet. Just noticing some intermittent slight banging, not bad, along with some vibration when it does it. Like about every 5-8 seconds. not all the time. Sounds and feels like it's coming from the lower pump assembly. Also my engine will only turn 2700 rpm's in the water. Out of the water with a water hose it will rev up as normal.
Also......I have a brand new powerhead (engine) with the auto oil injection taken off. It has 2 hours on it is all.
A lot going on here I k

Banging?? In the water or out?

If it's banging in the water, start by checking the reverse gate. In FORWARD, the reverse gate (bucket) bottom edge must be above the top of the jet stream. Check the cable ends and rubber bellows on shift and steering. You should also check all the bolts for tightness. Has the stator ever been off? Has the impeller nut ever been off? Is it tight?

When running out of the water, some rattle is normal.

BTW- how about the oil in gear box and stator?

About RPM-Should rev to 5800 in the water. It sounds like you may not be firing on all 6 cylinders. Is it due to fuel or spark? After you have run it a few minutes, feel the spark plugs. Hot ones? Cold ones? Take out and look at all spark plugs. Are they uniform? While the plugs are out, do a compression check. Must be done out of the water, all plugs out, at full throttle. Looking for 130psi.

These big 2-stroke engines should not be run over 2500rpm out of the water to prevent damage.

 

[bluetopper]

Banging and vibration is when it's in the water, intermittently but will not go over 2700 rpm's. I purchased the boat last year and had it out just a few times . The auto oil injection failed, busted an oil hose and ruined the powerhead. Got a new powerhead installed with auto oiling removed. Oil in stator is green and full. I'll remove oil from gearbox tomorrow. Ordered a new impeller socket tool and will remove it when the tool arrives. I plan on coating the inside of the wear ring with JB Weld. Tested the compression with a cold motor and getting about 98psi. I plan on changing the trigger also. I'm really not a boat mechanic at all. All help is appreciated.

 

[Tim75]

Banging and vibration is when it's in the water, intermittently but will not go over 2700 rpm's. I purchased the boat last year and had it out just a few times . The auto oil injection failed, busted an oil hose and ruined the powerhead. Got a new powerhead installed with auto oiling removed. Oil in stator is green and full. I'll remove oil from gearbox tomorrow. Ordered a new impeller socket tool and will remove it when the tool arrives. I plan on coating the inside of the wear ring with JB Weld. Tested the compression with a cold motor and getting about 98psi. I plan on changing the trigger also. I'm really not a boat mechanic at all. All help is appreciated.

98psi is very low. Was that done with all plugs out and wide open throttle? With a fully charged battery?

The impeller nut is very tight- 150 ft-# plus corrosion. After you remove the stator, replace the bolts. Do not remove the wear ring at this time. This will give some support to the impeller/shaft while you pull on it. Do not use an impact wrench. Do not strike the end of the shaft. Potential gear damage. Do not damage the end of the shaft. You may create an oil leak. On the shaft, in the tunnel are two flats for a wrench. This job takes two people. On re-assembly, be sure to grease the spline with Mercury Special #101 grease.

 

[bluetopper]

Compression was checked 2-3 weeks ago by a friend of mine who had a gauge and I think we had just one plug out and throttle in neutral and just turned it over enough to get a reading on the one cylinder. The powerhead was built last year by OBR Marine in FL I believe, and shipped to a local shop to be installed.
Thanks for the other advice!