evinrude 140 looper help

[revlimiter776]

hello all, todays question has to due with my engine upgrade, i recently removed a 70 evinrude looper to install a 140 looper, my question is this, what is the maximum rpm for a late 80's early 90's looper140. my trv pulled 40 flat with a 70 and a 18 raker, with the bullet about 6.5" below the transom, with the 140 about 5" below the transom, 1 am getting 50 flat with a 19" pitch @ 5600, and about 47 48 mph with a 21" hustler prop, the hustler i feel is crap, i know i have to get a jackplate and pick her up more, but i figured she should do better than 50 with a 140 and a 21 inch pitch prop, any teechnical info would be greatly appreciated.

[supergenius74]

I don't believe they build any more HP after 5500 RPM, I've ran my 140 as high as 6K when jacked all the way up but it doesnt seem to have any more power past about 5K rpm, I would suggest a higher pitch prop, use the torq of that V-4 and get the RPM's closer to 5K.

[Bruce]

Hi Guys, I have 92 Evinrude 120 which has the same numbers as the 140 (cu.in,bore,stroke), according to my Seloc manual it indicates wot 5000 - 6000 rpm. As you know, these are considered the "Big Block" v4's, lots of torque.,

Similar to SuperGenious, I can get my rpm's up to 6000 as well with trimming, but the speed does not really increase past 5500 or so, I gained a little bit extra going from a 22 Raker to a 24 Raker but lost the whole shot with the 24. I'm going to try a 4 Blade Renegade 23 in the Spring time. I have the Pulse 170 which goes about 53\54 GPS.

For What it's Worth

Bruce

[alwaysredee]

Prop and jackplate would be good. Remember though, There is no substitute for pure horsepower when harnessed correctly. Try a different prop first, find that combination and go from there. Good Luck! http://www.checkmate-boats.com/graemlins/thumb.gif

[Big Dave]

Originally posted by supergenius74:
I don't believe they build any more HP after 5500 RPM, I've ran my 140 as high as 6K when jacked all the way up but it doesnt seem to have any more power past about 5K rpm, I would suggest a higher pitch prop, use the torq of that V-4 and get the RPM's closer to 5K.

I would have to challenge that. Daren 34 and I put a looper140 with a cmc 6 inch hyd plate on his 80 diplomat. We were running 2 Raker props
22p 3b 6300 rpm
20p 3b 6800 rpm
without the jackplate, you could not hold on past about 4800 rpm because of chine walk.
We made alot of other brand boats very upset with that little bowrider.