Not sure where to start....

[jkeating]

Today, I finally got my boat out for the first time and have noticed a possible prop issue?

I have a 2015 crestliner Jon retriever (mod vee hull) with a 2015 75hp Mercury fourstroke.

Means it's the first time I have ever had it out on the water I noticed all the way up to 3/4 throttle it ran awesome with no issues at all. With no means of gauges on the dash I'm not sure on rpm, but coming over 3/4 throttle it seems the boat slows down as the motor revs higher like the prop is almost slipping or not catching enough water?

Prop wise it has a Solas 1411-133-17

If I were to reprop it what would a guy do to try to get full throttle with slipping?

Thanks in advance!

 

[GA_Boater]

This is a pretty new boat and motor. Doubtful the prop hub is spun, even though this has the symptoms.

How do you have the motor trimmed? Maybe trim the motor in and see what happens. If the trim is too far out, the prop could be cavitating.

 

[jkeating]

Well exactly what I thought... I don't quite think that's the case. Tried trimming it up and down and you go down anymore and the drag from the boat really slows you down, trim it up anymore and you start bouncing like a bobber. Now All the weight is in the back, 12 gallon fuel tank 2 guys and a battery so I made the other fellow sit up front and it planed out a lot better but the same deal was happening... Could it not be the right prop pitch?

 

[jkeating]

I'd really like to install a tach to see rpms... Only problem is the very smart boat place I bought the boat from ( which I will NEVER return or recommend anyone to ) decided to leave all the books sitting in the boat for weeks on end and got thrown away because the were soaked and the ink washed out and now on the throttle I'm not sure what wires go to what!

 

[GA_Boater]

Eliminate a spun hub by using a marker and drawing a straight line across the hub and prop. After you take her out and after it acts up, look at the line, If it isn't still lined up, the hub is spun.

Is this a brand new and freshly purchased boat? Tell them you want a set of manuals! They caused the books to be destroyed.

 

[jkeating]

I will have to try that. If it is a cavitation problem is there anything I could do? I figured after I get a tach wired in I could learn more about the boat and maybe reprop it? It's not a heavy boat, and usually only have 2 or 3 people in it..

 

[jkeating]

As for the books... I refuse and will not speak to the boat shop guy... I'm going to email Mercury and see if they will send me new ones.... The guys so stupid he promised me he would send in warranty paperwork for the motor over a month ago and he never did.. I called and asked and did it myself means the card was in the swamp of soaking books

 

[steelespike]

I wonder if the motor is mounted too high or maybe even too low.
The anti vent plate (just above the prop) should be about even with the bottom of the transom.
Final position will depend on the performance results.
While testing things get us a wot gps speed should help get an idea where your at.

 

[jkeating]

Well the cavitation plate on the motor when leveled is level with the bottom of the boat. I got a tiny tach in the mail today so hopefully can get an rpm. On the other hand I did get a gps reading of 36mph and hit 38mph but it started bouncing pretty bad since the lack of weight up front.

 

[fishin98]

Post a picture of the motor mounted on your boat. Sounds like it is mounted too high, you should not have slippage. Motors mounted too high for a extended time cause water starvation issue, hence burnt out powerheads. Go on Craig's list or Ebay...look at all the motors for sale that mention new powerheads. Stay on the person who sold you the boat for the proper books.