Is my motor governed down?

[Buster_boy]

Last year I bought a brand new 2017 18ft pontoon with a 2017 Mercury 9.9 EPLT Pro Kicker. At WOT it's running 2800-3000 rpm. I looked up the specs of that motor and Mercury says it should 5000-6000 max rpm. Why am I only getting 3000? Is my motor governed down so as to protect it?

Thanks
Jim

 

[jimmbo]

Perhaps you have the wrong prop for the load

A chat with the dealer may be in order

 

[Scott Danforth]

could only be running on one cylinder.

check compression
check for spark in both cylinders
check for fuel system restriction
make sure you have the right prop
make sure your height is correct.

since its a new boat, agree with jimmbo, have the dealer check these things. that is what warranty is for.

 

[tpenfield]

18 ft pontoon boat with a 9.9 HP engine . . . what's wrong with that picture? :noidea:

Put the engine on a 12 aluminum skiff and see what you get for WOT RPM.

 

[Chinewalker]

Agreed - check the propeller. That small of an engine on an 18' toon should have very low pitch prop on it. Assuming the small engine was chosen due to lake restrictions?

 

[Buster_boy]

Yes it is restricted waters 9.9hp 10mph max. It's a new motor too so I'd assume the prop came from Merc with the motor. It's a four blade pro kicker prop on a pro kicker motor.

I don't think it's a one cylinder issue as it was like this last year as well and was winterized last fall and serviced this spring by the dealer.

 

[Buster_boy]

Boat size shouldn't matter when it comes to rpm
rpm is rpm. Mph would.matter

 

[jimmbo]

Boat size shouldn't matter when it comes to rpm
rpm is rpm. Mph would.matter

Oh yes it will

 

[Buster_boy]

How is that? The motor/prop spins the same whether it's 12ft skiff or 18ft toon. How fast and how far it moves you I get, but motor speed is motor speed.

 

[tinner66]

Sounds like guardian is doing its job.
Read page 71 of your manual. It states 4 causes that guardian limits motor to 3000 rpms
1. low oil pressure
2.over speed condition due to cavitation
3.no load on propeller
4. under propped

 

[jimmbo]

Sounds like guardian is doing its job.
Read page 71 of your manual. It states 4 causes that guardian limits motor to 3000 rpms
1. low oil pressure
2.over speed condition due to cavitation
3.no load on propeller
4. under propped

As I said earlier, back to the Dealer to have a chat

 

[oldman570]

As I said earlier, back to the Dealer to have a chat

Over pitched prop or the weight of the load that the motor is pushing is why the motor can not reach the manufacture RPM rate of the motor. The dealer should have known this and told you that when you were buying the motor. A 9.5X7 pitch prop is about the smallest that can be bought to fit the motor. This is like a mouse pushing a wheel barrow loaded with rocks if the prop is any higher pitched, and still might be to much.

 

[tinner66]

pm sent

 

[tinner66]

Will it rev over three in neutral?

 

[Buster_boy]

I get about 3.5k in neutral. It's in the water so I can't see the pitch on the prop.

 

[tpenfield]

It has a throttle limiter in neutral, right ?

The heavy load of the pontoon boat is bogging the motor down. It is like a 4 cylinder car going up a steep hill in high gear.

Since there is a 10 HP restriction on the lake, the thing to do would be to get a lower pitch prop to try to get a little bit more out of the engine. But keep in mind, you only got 10 hp to push an 18 ft pontoon

 

[tinner66]

As stated in a earlier post it wont rev over 3500 in Neutral, that has nothing to do with the prop

 

[Buster_boy]

Ok. And that's really all I wanted to know. I know it's a little motor on a big boat. I just thought it was low and it wouldn't surprise me if my dealer governed it down so as to prevent damage while under warranty.

I suspect that because I bought the boat new last year -2017. It has a 24 gallon on board fuel tank. When he outfitted the boat he didn't connect the on board tank to the motor. Instead he connected a 3 gallon portable can.

His reasoning for that is 1) there is no fuel point on the body of water I'm docked on so it'd be easier to carry portable cans and connect them as opposed to trying to pour the cans into the tank while on the water and risk spilling, 2) given it's a 9.9 it'll take forever to use 24 gallons and this minimizes clogging the carbs, the fuel gelling, etc, and clean g the carbs is not covered under warranty.

I get it but he should have let me make those decisions.

 

[garbageguy]

Will it rev over three in neutral?

I am no engine expert, but do you really want to run it at high RPM's with no load on it?

 

[Buster_boy]

I only did that for about 5 seconds just to see what it would do.