Max power at what Revs?

Nasher · 06 April 2005, 20:05

Hi all

Can anyone confirm at what revs my old Johnson 150VRO should make max power.

I've only been able to get hold of a manual for a later 60Deg vee 150 and that makes max power at 5000 RPM.

I think 5K RPM is right for my old engine too, but wondered if anyone knows for sure.

Cheers

Nasher.

RIB BOI · 06 April 2005, 20:13

i reli dont no if this helps.

but i had a 140hp evn that did 5.5k to 6k revs it was a 1994 140 evenrude.

Josh

TIM · 06 April 2005, 20:26

Go on to www.boatsetup.com and in the Evinrude fourm , there is a few guys on that who will tell you anything you want to know about any Evinrude ever build ..... and if you give them the engine no, they could proably tell you who assembled it !!!!!

Nasher · 06 April 2005, 20:39

Tim

Hi, I've posted the same question there.

Josh

Thanks for that, perhaps I can get some more revs out of it.

Whilst I think about it, does anyone know how many pole alternator the engine has.
I thought it was 12 pole, but when I connected up the mercury tacho I got hold of, I had to switch it to the 4 cylinder position to get it to read anywhere near right.

Nasher

Wile E Coyote · 07 April 2005, 06:53

Nasher, if you can give me the model number of your motor, I should be able to answer all your questions as long as when you say "old" 140 it's not later than a 1991 model. I have the manuals for all 'Rudes and Johnsons up till 1991.

Alan · 07 April 2005, 11:13

Nasher, when I had a 150 GT VRO I think it rev'd to 5500 at least. 5k sounds too low, perhaps you are overpropped?

jwalker · 07 April 2005, 11:49

Nasher, if it's a standard 150 it max's out at 5000rpm (155hp). If it's a 150GT it max's at 5250rpm (175hp)

Nasher · 07 April 2005, 18:06

Thanks Guys, its a GT VRO 150 and its only reving to 5000 RPM with a 17inch prop which everyone is telling me is too small anyway.
Tried a 21inch which held it back to 4000RPM

Need to go away and think about this one.

Nasher

Alan · 07 April 2005, 18:16

Nasher, my memory is fading these days but I think we ran a 17inch pitch prop on our GT150 on the Deep Sea 21. I seem to recall we couldnt spin a 19 at full revs. I know we played around with props to try and maximise fuel efficiency and then came to the conclusion that it made b*gger all difference as the blimmin thing drank gallons of unleaded whatever we did

Nasher · 07 April 2005, 21:38

Alan

Hi, it certainly does drink petrol.

I've been trying to keep it going on the cheap whilst also atempting to replace it with a new tech 2-stroke at a bargin price, more of that another time.

Didn't realise my GT150 was actually a 175HP, makes the performance even more dissapointing.

Nasher

Tims Osprey · 08 April 2005, 10:41

Nasher, It sounds to me like the problem could be elsewhere all this changing props and rev counting should have produced results by now, with a set up like yours a few hundred RPM,s is not going to make a great deal of differance to your top speed. Is the boat left on the water or kept on the trailer?.

Nasher · 08 April 2005, 11:27

Tims

Hi, the boat is on a trailer not left on the water.
I've had an idea though.

The engine was serviced apparently before I brought it, and I'm wondering if its been set up to standard 150 spec not GT spec.
Its odd that the adjuster on the advance /retard mechanism is right at one end of its travel reducing the maximum travel so that after half throttle the ignition is effectivly fixed.
Don't want to start holing pistons etc, but will try allowing a small amount more to see if it makes a differance.

I'm also going to try removing the fuel filter/water seperator to see if its reducing fuel flow.
I'll put a bigger one in if it runs better without it.

Nasher

Tims Osprey · 08 April 2005, 18:31

Bye the way i had one of them fatacraft force 4's mine had a 30 suzuki and went fast yours must have flown with that 55 suzi how much did you get for it in the end?.