Yamaha T50 won't exceed 3500 rpm

[tkvoice]

I have a 2005 Yamaha 50hp outboard model: T50TLRD. EFI four stroke.
At wide open throttle the engine peaks at 3500 rpm.
I am thinking it should go 4500-5000 rpm
The engine starts right away and seems to be running smooth on all 4 cylinders (no shaking or misfires).
I just bought this 50hp outboard so I'm not familiar with historical Max RPM speeds. Is 3500 rpm all I can expect from a 50hp Yamaha?

 

[racerone]

What boat is it on?----What pitch is the prop?-----And post the actual vales of a compression test.

 

[tkvoice]

Brand new Aluminum prop 13.25" diameter with 17-pitch
I have never done a compression test but this engine only has about 400 hours starts instantly never burns any oil the outboard is in very good condition. Just had oil change and lower unit gear lube change.
There is nothing wrapped in my prop I can spin it freely with ease. There's nothing plugging up my water intake or exhaust the whole engine's been gone through just came out of winter storage

 

[tkvoice]

The boat is a 2005 Bennington 2050RL pontoon apx 2000lbs & 20 ft long. It gets going 13 miles per hour according to the GPS speedometer on my phone at 3500 RPM

 

[racerone]

Perhaps you need to talk to a prop expert.-----If the motor is in " perfect condition " you have the wrong prop to fit the boat.

 

[99yam40]

a t50 pushing a 20 ft pontoon?
not much motor .
have you looked at what other people are pushing a boat like yours with?
also what prop they used?

look at yamaha performance bulitens online to see if they list a T50 for a toon like yours ,
and if so what prop that used.

 

[tkvoice]

50hp "high thrust" came stock from pontoon manufacturer. Even brand new pontoons today come with 50hp.
Of course they have other size outboards available but 50-115hp is pretty typical.

 

[racerone]

Who decided that the 17" pitch prop was the one to fit this pontoon boat ?

 

[tkvoice]

I could not find any Yamaha Performance bulletins for my setup. They have one for a 70hp pontoon

F70LA on Godfrey Sweetwater SW 2086FC Performance - Yamaha Outboards

Find detailed specs and performance information for the Yamaha F70LA outboard motor paired with a Godfrey Sweetwater SW 2086FC boat.

yamahaoutboards.com

and 40hp pontoon

40-30 HP Midrange Outboard Motors - Yamaha Outboards

The portable series four-stroke Yamaha outboard ranges in horsepower: 25HP, 20HP, and 15HP. This motor is lightweight but can haul a heavier load boat.

yamahaoutboards.com

 

[tkvoice]

The propeller came with the boat. (bought boat used)
Using the Solas propeller finder it recommends I use 14"diameter with pitch between 9-11.

Prop Finder

SOLAS® is the most well known and trusted name in outboard and stern drive propellers in the world. Available as SOLAS® Brand traditional single piece pressed rubber hub, or RUBEX® Brand interchangeable rubber hub boat propellers.

www.solaspropellers.com

 

[99yam40]

Only T50 I found listed was on a 15'7" toon
I would not be expecting much on a 20'

60-9.9 HP High Thrust Outboard Motors - Yamaha Outboards

The High Trust four-stroke Yamaha outboard ranges in horsepower: 60HP, 50HP, 25HP, and 9.9HP. It is designed for heavy boats that require more thrust.

yamahaoutboards.com

 

[tkvoice]

Update
I put a 10pitch prop on and now I get 4500rpm and 17mph much better but still a little shy of 5500rpm.
Some manufacturers have 8 or 9 pitch but at this point it probably won't make much of a difference. I guess it's just too heavy of a boat.

 

[racerone]

Are you 100% sure this motor is in good condition ?

 

[cyclops222]

You need a GPS handheld to get ACTUAL speed in the water. Corrected for any river currents. Low wind speed. Less than 5 mph. How accurate is the boat tachometer ?

 

[99yam40]

what is the HP rating for the boat?

Probably too small of a motor for that size boat ,
The reason you could not find a performance Bulletin for it with a T50