Want less speed

[belairbrian]

I know, it sounds strange most want to go faster.

Here is what I have.

18.5 ft v-hull center console ( Winner 1850)
140 hp johnson v4
WOT is 5000 to 5200 rpm
speed is 40 mph (GPS) 42 (pitot)
prop is OEM 14x17

I can throttle back 40 around 4000rpm and go 34 mph

Would like to run a little slower.
I was thinking 14 x 15.

 

[NHGuy]

Re: Want less speed

That pro pitch will go slower, but use more engine revs at the same speed. This means it will use more fuel. But on the bright side it will accelerate to that speed better.
I'd not change the prop unless you need a better hole shot, or towing for watersports.

 

[Silvertip]

Re: Want less speed

That's what you have a throttle for. Just like your car -- to go slower you don't step on the gas as hard. It doesn't make sense to make the engine run wide open to go slower. In a car that would be the same as never using overdrive regardless where you were.

 

[Tacklewasher]

Re: Want less speed

I know, it sounds strange most want to go faster.

Here is what I have.

18.5 ft v-hull center console ( Winner 1850)
140 hp johnson v4
WOT is 5000 to 5200 rpm
speed is 40 mph (GPS) 42 (pitot)
prop is OEM 14x17

I can throttle back 40 around 4000rpm and go 34 mph

Would like to run a little slower.
I was thinking 14 x 15.

Either you are set up almost perfect, or something is off with your numbers.

40 mph @ 5200 rpm with a 17p prop is under 5% slip.

[FONT=&quot]I run a 15p on my 1980 115 on a 18' Starcraft and get around 5800 rpm and just under 40 mph. But I put a lot of effort into my setup.[/FONT]
[FONT=&quot]Bigger issue is you are only seeing 5000-5200 rpm at WOT.

By going to a 15p prop you should see 5400-5600 and that is a better rpm to be running at wot and will stop your engine from lugging.

Others brighter than I am suggest running these motors 5500-6000 rpm so I'd look at switching. Not sure what impact it will have on speed though.


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