Pontoon Boat & Deck Boat Forum

I am asking for your advice to see if I have an issue or not. I have a 22 foot 2004 Crest Caribbean powered with a 2005 Mercury 115 HP ELPTO (2 stroke). The prop is a Mercury Vengeance 48-16986 16P. We keep the boat in the water year-round. The tubes are pretty clean as we cleaned them last week. I have been complaining about the speed of the boat since we purchased it new. We have run at 4200 RPMs most of the time unless we are trolling for crappie. At 4200 RPM, our speed is between 12 to 17 MPH depending on the cleanliness of the tubes. Mostly in the 13 to 14 MPH range with a medium load. This year, we have focused on keeping the tubes clean. Even after our dealer cleans the tubes, we cannot hit 20 MPH. We are also adding the Quicksilver Fuelcare to the fuel to each tank.

Today with clean tubes, at 4200 RPMs the speed was about 15 MPG (GPS). With WOT, the RPMs were 4600 and my top speed was 16.5 mph. The top is folded and in its cover.
Saturday, we ran about 10 to 12 miles at 4200 to 4400 RPMs and burned about 12.5 gallons of gas. The bimini top was down.

In looking at http://pontoonguide.com/how-fast-pontoon-boat-speeds/, I think I should be in the 20 to 25 MPH range. Am I correct for this boat?

I would appreciate any suggestions as how to improve speed. Thank you, in advance, for your input. I do appreciate it.

RPM is too low, that motor should be able to turn much higher perhaps 5,500 to 5,800 (check your manual for max RPM) If your engine is lugging and it sounds like it is you will burn a lot of fuel.... I think without any other hidden issues that you have TOO MUCH pitch on your prop...

I also agree about changing the propeller as your rpm's are abnormally low.

My question is how are you trimming the motor out? If you don't keep the anticavitation plate parallel with the bottom of the boat or higher, you may find yourself plowing through the water--lowering mph.

Remember this is a 2 stroke, and they don't turn the rpm's that the 4 strokes do. While I don't know your posted redline, 5500-5800 rpm's are more normal for 2 strokes, and you should try to get up there too.

You should be a propeller and a good bottom cleaning from the mid twenties--if your engine's running right. My Yamaha 115 hp 2 stroke on a 24' Starcraft was a 30 mph toon.

I have a 22' crest with a 90 hp johnson 2 stroke and it will run 20-25 with clean to half cruddy toons. I "think" I have a 13 pitch prop by mecr. for pontoons with extra cup. I agree with the 5500-5800 rpms,also even one person up front will kill all speed.....good luck

Thank you for the responses. I have been complaining about speed since we purchased the boat.

I do trim the motor to try to improve speed. I adjust the trim until I find the highest speed I can hit. It does not take much trim.

I also use one of these..Sting Ray XRIII Senior Hydrofoil Stabilizer ... it gives a little more trim,keeps the nose up and helps in turns and its no drill....

War Eagle78 wrote:Thank you for the responses. I have been complaining about speed since we purchased the boat.

I do trim the motor to try to improve speed. I adjust the trim until I find the highest speed I can hit. It does not take much trim.

To whom are you complaining?

Dealer

had a similar Crest 2004 Crest LM II 115 Evinrude the prop pitch 13 was 5900 rpm speed 27 mph (GPS)
you should be able to get 24 mph out of that with the correct pitch prop.

I'm running a 24' Crest with a 4 stroke Merc 115. I can max out at 24 mph at 6400 RPM.

Thank you for the responses.

We are looking at options to improve the performance. Mercury customer support told me I should be in the 5250 RPM range at WOT. He cautioned that I could spend a lot of money and not get a big increase in speed. We are going to try some different props.

Thank you again for your help. I appreciate the advice.

Not a technical guy at all but when I was looking to purchase a toon I vaguely remember the Crest brand weighs quite a bit more than other toons? Not sure if that is true, but I Would think if it is, that might also play into the top speed...?

I thought I would give an update:

This week my repair shop fixed a small leak in the oil line. The check valve had a small crack in it and oil was in the carbs (I think) They found a issue with the throttle cable...it was slipping. They found the tach is sticking. The tach will not read above 4600 RPM. The shop measured the RPMs up to 6200. New tach ordered. Bottom was pretty clean considering the tunes were cleaned professionally in late May.

They also did some work on the prop.

The motor is quieter. The throttle is more sensitive and responsive. Speed has improved about 3 to 4 MPH. At WOT, I am doing between 20 and 21 mpg. At the tach reading 4200 RPMs, I am up to 16.5 MPH in a 5 to 10 mph headwind. I am usually at 12 to 13 mph this time of year.

Thank you.

Yeah not knowing accurate RPM can sure lead you astray on knowing IF you even have an issue our not....

BUT I now wonder about the diameter of your prop being too small as I see it is only a 13.125" x 16P prop and to be honest with you while I'm no prop expert I would expect to see at least a 14" diameter being swung by a 115 motor. The prop you have all but sounds ideal on a small planing hull. In fact it is almost the same as what's on my 16-ft V-Hull with a 90 HP motor...

Eh but maybe not as your prop does come up as one of the recommended props using the Mercury prop calculator....