Need more speed

[tomisolomi]

I have a 1990 18ft Cajun Tournament Series bass boat with a Mercury 150 XR2 motor a Ballistic 14 3/4 x 15 prop set 3.5 inches below pad. I can only get 41 mph, what can I do to get more top end I would like to get 60 or is this top speed for this boat?

 

[the vision]

Re: Need more speed

Try a 19 degree prop would probably help.

 

[Fingerlakes]

Re: Need more speed

That sounds a tad slow. You GPS your speed or are you going by the boat? I had a 21 foot Switzer with a 200 Merc, jack plate and a 28 pitch Spinelli chop prop on it. I could get 65 out of it. I would go in the direction of a higher pitch prop.

 

[tomisolomi]

Re: Need more speed

41 mph gps speed might try a 25 pitch prop not sure if I can get recomended rpm though

 

[Mi duckdown]

Re: Need more speed

You should ask this in the prop section. But gps speed and correct rpms are needed.

 

[Fingerlakes]

Re: Need more speed

41 mph gps speed might try a 25 pitch prop not sure if I can get recomended rpm though

You may want to go to a bass boat forum and try and find someone with a similar setup and see what they are using. A 25 is a big jump from what you have. Like mentioned above, you may want to start with 19 and then move up if necessary. With the prop you're using now, I'm not surprised with the speed you're getting.

 

[jestor68]

Re: Need more speed

I have a 1990 18ft Cajun Tournament Series bass boat with a Mercury 150 XR2 motor a Ballistic 14 3/4 x 15 prop set 3.5 inches below pad.

If the prop is 3.5 inches below the pad, you're not going anywhere very fast.

 

[5150abf]

Re: Need more speed

Before you go buying a new prop, what rpms are you turning right now at wide open throttle?

You prop a boat to achieve an rpm not for speed.

And yes, if your cavitation plate is 3 1/2'' below the boat it is too low, you should raise it to level or slightly above.

Have you checked the boat for water logging, water logged foam will add hundreds of pounds to the boat and slow you way down and lastly are you sure the engine is running correctly?

 

[Philster]

Re: Need more speed

tom, if you need more speed, come back with results from a wide-ope-throttle run, which includes GPS speed and engine RPM.

Make the run in several directions and note the speeds and engine RPM.

Lacking that, no one is capable of addressing the issue.

The PROP, people, is 3.5" below and is a good ballpark starting point for a boat like that. The AV plate NOT below.

SO: engine RPM and wide-open-throttle along with the top speed. Barring that, the thread is dead.

We'll wait..........................

 

[tomisolomi]

Re: Need more speed

41 is gps speed running 5500 at WOT

 

[Philster]

Re: Need more speed

Well, you are turning 5500 RPM which is the bottom of the max RPM range -- Barely acceptable.

On a 22 year-old boat, you have to ensure that the engine is healthy and running properly and that the boat is not heavy and waterlogged. They are your next steps, but in the meantime, some smaller things to check:

The boat and engine should be clean and smooth on the outside.

The engine can probably come up 2" to see if she squeezes out another 2-3 MPH and little more RPM.

No way in heck a smaller prop is proper. A bigger prop would dog the engine and be worse in all cases.

 

[5150abf]

Re: Need more speed

Is ther prop slipping or something, that just doesn't sound right, I have a 16' aluminum with a 50 and it will go 30, you have 2 more feet of boat and 3 times the power but are only going 11 mph faster, something doesn't add up.

I know alot of people think any boat problem is a spun hub but that would be a good thing to check in this instance, that boat should be going 50-60, not water logged, engine correct.