Whale Tail

[CustomBaitPainter]

I purchased a used 1984 stratos 375v , 1988 mariner 115 in-line 6. The owner said he never ran the motor wide open, He said tops for him was 40 to 45 mph @ 3500-3800rpm. The motor has a whale tail / ss rapture prop , he didn't recall the size/pitch of the prop. Anyone know what kinda rpm's / speed this boat should be getting? should I remove the whale tail? There's a manual jack plate, the motor is sitting all the way down, looks about 5 to 7 inches below the hull.

Thanks For Any Help

Mike P.

 

[Strato-G]

Try it like it sits, u may be happy, remember, an older engine is like older fisherpersons, it is accoustomed to the current RPM's, you may want to take your time in getting it wound out tight, be easy on the older unit, check foot oil before running hard, probably should be changed, look for water when you drain the lube......luck....... emoGeezer emoUSA

 

[dragfish]

Strato-G - 3/6/2012 7:38 PM

check foot oil before running hard, probably should be changed, look for water when you drain the lube......luck....... emoGeezer emoUSA

Excellent advice!! Do it ASAP

 

[CustomBaitPainter]

Everything has been changed , plugs, water pump, lower unit oil, carb's rebuilt, compression 115-119 all 6 cyc's .

Mike P.

 

[Strato-G]

CustomBaitPainter - 3/6/2012 8:12 PM

Everything has been changed , plugs, water pump, lower unit oil, carb's rebuilt, compression 115-119 all 6 cyc's .

Mike P.

Looks as u have made the right choices, just try like is and gradually take it up and feel how everything settles in, u may be happy as is...... emoGeezer emoUSA

 

[churly]

the whale tail was probably put on to prevent cavitation or porpoising...papaw also may have used it to keep the boat on pad at low speeds. They usually take away from top end spend.

 

[wrechin2]

Do not run it over 6K. That engine by design is not a RPM engine. You should have it set up to turn around 5400-5800 RPM's. If the "wail tail" is running below the surface of the water it wil slow you down. I took mine off a similiar set up and gained 5mph from the removal of the drag. If it is above the water or just at the surface you will not see a big difference.

Measure the engine height. On level ground take a level an place on the bottom of the boat and raise/lower the trailer jack until it is level. Place the level on the caviatation plate ( what the wail tail is mounted to) and level it with the trim. Now measure from the ground to the bottom of the boat and then from the ground to the center of the prop shaft. The difference will tell you how deep you engine is. MOST boats run well at 2.5 to 3.5 below the pad. But all boats are different and this would be a good starting point.

Also make sure you run a cleanner such as seafam or berrymans as those engines are very bad about carboning up due to the design of the pistons.

 

[CustomBaitPainter]

Hey wrechin2
Do I add the seafoam to my gas and/or spray it into my carb's ?

Thanks Mike P.

 

[Auburnwes]

You add it to your gas.

 

[wrechin2]

As Wes replied, add it to your gas and keep it in there. This will prevent/repair a lot of issues.

 

[CustomBaitPainter]

So, every time I put gas in my boat add some seafoam ? This means I don't have to use sta-bil ?

Mike

 

[wrechin2]

Stabil is for storage. I personally prefer the Berrymans as it is cheaper and treats more gallons of fuel and have had numerous sucess stories from people using it. It is cheap enough to add it every time you add fuel. Just my .02

 

[CustomBaitPainter]

Hey James

Is that the B12 stuff ???

Thanks Mike

 

[wrechin2]

YEP!