Volvo Aquamatic 270 prop problem

[ned2nav]

Hello all, I am having a bit of trouble with a 19 foot 1984 sunbird eurosport bowrider. At the current time it has a 350 chevy engine with a volvo augamatic 270 outdrive. The prop size is 15 x 19. The problem is that the boat takes for ever to plane, and the rpms are super high. For example, in order for the boat to plane i need to push the rpms up to 3500, yet when it planes it does not go faster then maybe 20 knots. The WOT rpms can not be determined due to the fact that the engine will explode, the engine has been pushed as far as 4400 rpms with power to spare.<br /><br />Could it be the size of the prop, the pitch, or both?

 

[dick]

Re: Volvo Aquamatic 270 prop problem

A little more info please.Are you new to the boat? Has the prop or drive been changed recently ?Did this just start or has it always been like this ?There are many things it could be from the hub in the prop slipping to the cone in the drive slipping .That prop on the drive now should be pretty close for that size boat.

 

[airman]

Re: Volvo Aquamatic 270 prop problem

I agree, it sounds like your prop hub is slipping, or possibly the clutch cones. To test, put the drive in gear (engine off) and try to turn the prop by hand. It will turn easily one way but shouldn't move at all the other. If it does move, look to see if the prop blades are slipping on the hub (bad prop) or if the hub is turning too (bad clutch).

 

[ned2nav]

Re: Volvo Aquamatic 270 prop problem

Sorry about that. This boat has just been aquired, and it is the first time i have been able to test it. Someone also told me that it could be the gearing in the sterndrive. That the gearing was designed for a smaller engine and will not give me enough revolutions on the prop itself. Do you know what gear ratio these drives came with? Also, thank you for the advise, i will try the steps you mentioned.

 

[ned2nav]

Re: Volvo Aquamatic 270 prop problem

The procedures mentioned above, to check and see if the prop or the clutch cones were bad. As mentioned it moves easily one way, but it will not move the other way.

 

[dick]

Re: Volvo Aquamatic 270 prop problem

Soneone could have put a different drive on .Check to see if there is a serial # tag on the leg. It's located under steering helmet just after the u-jiont bellows aft of the boat(you may have remove the allen head bolt that holds the helmet to the drive to read it.I think It should be a 1.68 ratio but will check today.

 

[dick]

Re: Volvo Aquamatic 270 prop problem

Sorry thats a 1.61 ratio.