Speed & RPM not good

[ondarvr]

I just mounted a 200HP V6 Evinrude on my 19' Blue Wave bay boat, WOT RPM and speed are far lower than expected. with a 14.25 x21 (AL) rpm was 4700, speed 42, with 15x17 rpm is 5400 at 44 mph. Motor runs fine, pulled heads and exhaust cover all clean, no blow by, carbs rebuilt twice, compresion 112 +/- 3. AV plate 1.75" above hull. new teleflex tach set on 6. Speed was with paddle wheel, forgot the GPS at home. Hull 1,200 lbs, 8 gallons of fuel and one person. should be 50+ easy. What do I need to look at now.

Thanks

[Rickracer]

I believe it should be set on 12 pole. Also, you need to think about moving to a SS prop. Probably a 19 or 21. If you have the opportunity to try either one, do it. You'll like the difference. :cool:

[ondarvr]

Thanks for the responce. The instructions with the tach say 6, low speed and idle rpm seem to be correct at 650 to 700 rpm. I had the aluminum 21P so I started there expecting around 50mph, and 5,500 rpm. Then I was going to dial it in with a SS Prop, but when I couldn't go over 42mph at 4700rpm I thought there might be something more going on and didn't want to buy an SS prop until I could get better numbers with aluminum. I think (know) I can get better numbers with a V4 than what I am getting with this V6. If I can dial this motor in I will keep it, if not, I will look for another one. A V6 uses too much fuel to only go 44mph. I will try to find a SS 19P and see what happens

I am looking for any help I can get.

Thanks again

[Rickracer]

....check your timing and carb synch, and make sure you're getting WOT out of your throttle. I bought a "Tron CVX20 and 235 OMC one time that the previous owner told me would do 55 period. After having it out one time, it didn't feel right so I started checking, apparently it had been running on 5 cylinders for years. After a little tuning, and the addition of a 6" jackplate, I took him for a 70 mph ride. Needless to say, he was shocked. I think you'll probably wind up with a 21" or 22" SS prop. :cool:

[tomoad]

right on rickracer, sounds like your not running on all the cylinders, i am a black motor fan, but i know that 200 omc should be pushing her better than 45 or 50 mph, or the boat is just plowing the water. let us know what you find

[ondarvr]

On the first test run I noticed a miss and found that 4 of the coils were cracked, on the next run after 6 new coils, I was up to these numbers (the ones listed in the first post), this was a gain of around 400 rpm. At an idle I pulled off each plug wire one at a time and got a slight drop in rpm each time. I then did the same test, only this time I took it to WOT, with all six conected it was 5,400 rpm, with one plug wire pulled off (any one of them) it was about 5,000 +/- 50. I was checking to see if one cylinder was not pulling it's fair share under load. I will check the timing. The throttle is opening completely, at least it is when I check it when it's not running.


Thanks for the help

[ken medendorp]

I don't think your doing your ignition system (CDI) any good pulling a plug wire off unless your grounding out the plug wire.Just something I was told

[ondarvr]

I mounted a small stud on the exhaust cover so I could put each plug wire on it while testing, I didn't know if it would harm the ignition and I didn't want the wire flying around a speed.

Thanks

[Tom D.]

I've got a Raker 14 1/2x20 for sale in the Propeller section. Check it out it might be the ticket for you.

Tom