First real run and questions.

[Tacklewasher]

Went out tonight for my first real run with this boat/motor combination.<br /><br />Only hit about 33 mph turning 5500 rpm which suggests a 33% slip. Had to trim all the way up to hit 5500 and was leaving a rooster tail as I went.<br /><br />Also, had trouble taking off from anything but a dead stop. It seemed the prop would either vent or slip, and I just wasn't going anywhere.<br /><br />I'm thinking prop slip is the problem and will be checking for that on Saturday. Sound like I'm on the right track?<br /><br />Prop is a 13X19 SST that I just picked up used. The prop that came with the motor had a bent blade and caused a real vibration. Pretty much junk.<br /><br />I will post pictures tomorrow looking at how high the motor is, but I'm also thinking of moving it up one hole, but I want to test the prop first.

 

[DJ]

Re: First real run and questions.

TW,<br /><br />A "roostertail" can be caused by two things.<br /><br />1. Engine "overtrimmed".<br /><br />2. Engine too low causing excess spash around the cavitation plate.<br /><br />Which one do you think you have?

 

[BF]

Re: First real run and questions.

I'd check to make sure that the hub on the prop you bought isn't spun. (maybe that what you meant by checking for prop slip). The prop with the bent blade, is it aluminum or stainless? If aluminum, it can be fixed to be as good as new (here it costs ~$40)<br /><br />I run a 19" pitch 3 blade aluminum prop on my boat (17' fiberglass ski boat, with V150 merc)... at 5500 I'm doin mid 40's (without much trim)... trimming gets me low 50's. Your motor could have a different gear ratio than mine, that would change things. But still, you should be in the 40's I'd think.<br /><br />HTH

 

[Tacklewasher]

Re: First real run and questions.

Slip/spun. I'll get the terminology down one day but, yes that is what I'm thinking. <br /><br />I'm going to mark the hub and try it (probably Saturday, I'm doing a waterpump on my truck).<br /><br />The old prop has been rebuilt a couple of times from the looks of it, plus I cannot see what pitch it is. The stamp may be just covered in loads of paint but it seems too far gone to be of use. <br /><br />As to the rooster tail, I think I'm overtrimmed but because the engine needs to move up a hole.