150 Evinrude blowing out of water

Mike150evin · May 23, 2009

Need help please! I have a 93 Stratos F&S with a 92 150 evinrude. For some reason it seems as the prop is lossing it's bite. When this happens water pressure drops and rpm's rev up. I have tried the following, replaced prop and lowered motor but still have problem. It doesn't do it at all times. I ran the boat at 49 mph for several minutes and it ran great after fishing for a while and headed back it done it again. It just comes and goes. Any info would be greatly appreciated. Thanks

tashasdaddy · May 23, 2009

Re: 150 Evinrude blowing out of water

does it just slip, or does it make a bang, and feel like it hit a log? has the lower unit been off recently?

Chris1956 · May 23, 2009

Re: 150 Evinrude blowing out of water

49MPH is pretty fast. Normally that speed is associated with an engine that is installed quite high on the transom. Look to see where the anti-ventilation plate is in relation to the bottom of the hull. It should be 1" above the hull, or so, on normal boats. High performance boats have the motor mounted higher.

The motor may still be too high.

wilde1j · May 23, 2009

Re: 150 Evinrude blowing out of water

The cavitation plate should just be uncovered at high speed. If it's buried, the motor's too deep. It's possible your motor is too high, and you might try lowering it one hole. The trim may be set with too much kickout, which will also cause a prop to break free and cavitate.

R.Johnson · May 23, 2009

Re: 150 Evinrude blowing out of water

What kind of prop are you running? Aluminum, or stainless steel. Have you added anything to the transom such as a transducer, or speedometer pick-up? These can induce air into the prop stream if mounted to close to the gearcase.

Mike150evin · May 23, 2009

Re: 150 Evinrude blowing out of water

R.Johnson said:
What kind of prop are you running? Aluminum, or stainless steel. Have you added anything to the transom such as a transducer, or speedometer pick-up? These can induce air into the prop stream if mounted to close to the gearcase.

I'm running a new ss solas 14.5 x 21. I have replaced a trasducer with a different brand that has a different shape and it is off center of hull maybe 5 inches. I have wonder if this might be it.

Mike150evin · May 23, 2009

Re: 150 Evinrude blowing out of water

tashasdaddy said:
does it just slip, or does it make a bang, and feel like it hit a log? has the lower unit been off recently?

None of the above, it runs great then it has it's moment. some days it wont even do it and some days it will. Seem worse when lake is calm no wind.

ondarvr · May 23, 2009

Re: 150 Evinrude blowing out of water

5 inches off center would still be right in the path of the prop, the different shape may be what the problem is. You'll need to move it further over.

You could take it off and run it to see if that's what the problem is.

wilde1j · May 23, 2009

Re: 150 Evinrude blowing out of water

Motor clearly should be centered.

R.Johnson · May 23, 2009

Re: 150 Evinrude blowing out of water

Remove the transducer, and see what happens. If it is dragging the water, it could be the problem.

Mike150evin · May 23, 2009

Re: 150 Evinrude blowing out of water

R.Johnson said:
Remove the transducer, and see what happens. If it is dragging the water, it could be the problem.

I moved my transducer 15" off center to the right. I did notice that the transducer had become lose and was turned to one side badly. Headed to the lake first thing in the morning. I will get back with results asap. Thanks for everyones input. Great web site!

Mike150evin · May 25, 2009

Re: 150 Evinrude blowing out of water

Turned out to be the transducer. I carried boat out and ran it hard all day and no cavitation. Thanks you all for your help!

150 Evinrude blowing out of water

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