Pontoon Prop Help Please

[R H Cotton]

I have 20 ft. osprey fishing pontoon. The total average weight of boat, motor, people and gear is 2100 lbs. I have a 14x11 sst prop that will deliver 4600 rpms at wot with a 2007 75 hp e-tec motor. I understand that a prop that is called "Hydrus" is specially made for pontoon use. I feel that my rpms need to be increased. Is the Hydrus prop also sst and does anyone out there know if changing to this will help me? If so please recommend diameter and pitch. Ant help or suggestions will be appreciated.

 

[steelespike]

Re: Pontoon Prop Help Please

I'm not a prop expert but::Something isn't right.I have a Etec report on a
50 hp on a 20' Premier 1800 lbs dry w/o motor motor=240.30 gal fuel 200 lb man 50 lb gear a 14 X13 aluminum 3 blade prop turns 5,600 rpm at 21 mph.The aluminum prop has a little less bite than the SS but I would think a 14 X 11 SS would let it rev.I wonder if your set up needs some fine tuning.
I also have a test with a 115 on a 22ft Crest 2,500 lbs. dry w/o engine.
13 3/4 X 13 al. 5,630 at 29 mph.Engine = 369,man 250,fuel 24 gal,gear=20,2 grp 27 bats. Unfortunately no 75hp test but it would seem to me you should be at least in the 5,000+ range.
Motor may need to be raised.trimmed?

 

[walleyehed]

Re: Pontoon Prop Help Please

R H Cotton, the Hydrus is a great prop for toons and house boats, but it sounds like you may have some other issues...first, let's make sure you have 30-40hrs on that engine. If you do then we need to look at why it's only getting 4600... I'm fairly certain it should be doing better with an 11P on that combo. might want to verify the tach is on the correct setting.
What is your idle RPM in gear?

 

[R H Cotton]

Re: Pontoon Prop Help Please

I will check out what the idle rpms in gear are this weekend. What rpms should I be getting .Thank you.

 

[walleyehed]

Re: Pontoon Prop Help Please

I'm not positive on that etec, but I'd guess 700, maybe 750 in gear.

 

[Silvertip]

Re: Pontoon Prop Help Please

I suspect the tach is not correct. As everyone suggests, that 11P prop should allow the engine to spin up with no problem.

 

[R H Cotton]

Re: Pontoon Prop Help Please

I checked several things on the pontoon as suggested. With just me in the boat I could get 4800 rpms out of the motor. It dropped down to 4650 with one other person in the boat. The idle rpms are right on the money in neutral and idling in gear. They were 600 and 700 respectively. From the waterline at the toons to the center of the prop is 21 inches with two people onboard. Does this sound correct? The prop is in like new shape. It is a 14x11 sst. The boat will run 21 mph with 3 miles per gallon running at 4650 rpms. Also does this sound about right for a 75hp E-Tec? I appreciate the responses that I received when asking for advice. With this added information all help and suggestions will appreciated on this matter.

 

[steelespike]

Re: Pontoon Prop Help Please

Rpm range is 4,500 to 5,500 so your in the range.Maybe if you raise the motor one hole at a time it might pick up some more rpm.I'd keep raising it until venting becomes a problem.just be sure it pumps water.I don't think you need a prop change on that relatively small toon.I just went back and checked the Etec 50 on a 23ft toon.it turns 5,350 with a 13 3/4 13 stainless.19.5 mph.3.8 mpg. again 2455 lbs dry.Maybe yours is squating and dragging supports or something.Try all kinds of trim.

 

[Rancherlee]

Re: Pontoon Prop Help Please

Something is wrong with your setup and you should be getting well over 21mph out of that setup. My parents have a 20' pontoon thats around ~1800lbs with a Yamaha 50hp 2 stroke on the back that will cruise along at 23-24mph gps with 2 people on it. You have 25 more hp and not much more weight. Does this have Very large diameter pontoons? (more drag)

 

[R H Cotton]

Re: Pontoon Prop Help Please

They are 23 inch toons.

 

[steelespike]

Re: Pontoon Prop Help Please

I would think 23 in toons would help get it up a little better.Although toons don't really get up much.Has anyone checked to see if your cables are adjusted right advancing the throttle all the way.If your under warrantee take it to the dealer with a print out of the etec/toon performance tests and ask them how come.Something is up with the motor or setup.
If your motor could be raised as little as an inch you could gain a couple of miles per hour.And if it is really low it could gain more.both in height and speed.

 

[kp913]

Re: Pontoon Prop Help Please

The propeller seems correct for that set up for sure. Sounds like maybe too much lower unit in the water creating drag. I would take the suggestion of raising the motor hole by hole and see if your R's increase as you raise.

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[R H Cotton]

Re: Pontoon Prop Help Please

I raised the motor 1 notch and now my rpms are 5350 at wot with the 14x11 prop.I am considering raising one more notch to see if it will raise the rpms even more. If it doesn't vent and goes a little over the maximum recommended 5500 then wouldn't it be a good idea to consider getting a 14x13 prop? Would this give me a little more speed and better fuel economy?