75 or 90 h.p. 4 stroke Mercury outboards

[WalleyeManDan]

I AM LOOKING FOR ANY INFO. ABOUT THE NEW MERCURY 4 STROKE MOTORS . HOW LOW CAN THEY TROLL R.P.M. WISE. ARE THEY REAL SMOOTH AND QUIET. I HAVE USED AN EVENRUDE 70 4 STROKE THE PAST 2 SEASONS BUT WOULD LIKE A LITTLE MORE TOP END. HOW WOULD A MERCURY 75 OR 90 4 STROKE COMPARE. THANKS FOR ANY HELP.

[Fred_G]

I have a 2001 Mercury 75 4 stroke on a 1700 Angler. My top end is 5400 - 5500 rpm's and 42 mph. I have a 15 pitch aluminum prop. The motor is very smooth and quiet. As for trolling speed, the lowest I have gotten down to is about 1,000 rpm's (about 2.5 mph). Fred

[mike]

Fred,

FYI, you can adjust the throttle on this motor and bring your idle speed down to 650-700 r's, doing so will also slow your troll speed. I've got a yamaha f80 which is essentially the same motor, I think these are great engines!

[Bruce]

It may be true that your idle speed is to high but check your manual prior to making any adjustments. I have the same motor and I am 90% sure that you want 850 rpm by the book. As stated before this will help you with your trolling speed some.

As far as the motor goes I have had some small problems. I have been watching this board and have checked all the past post and I think that I am the only one that has had any troubles. I think that this is more of a lack of having a decent mechanic to fix a small probelm.

One thing to remember if you buy a Merc 75 or 90 HP 4-stroke. These things (4 strokes in general) are still new and have different operating characteristics than the 2 strokes and therfore it takes some trial and error to get the right prop for the setup you have.

Currently I think that we have the problems worked out and things seam to be running well.

If you are going to up the HP you might as well opt for the 90.

Good luck.

[Pat]

Fred is your boat a 1700 Angler as stated, or could it be a 1700 Angler SS? I have the SS model with a 75 HP Honda and am not getting quite the speed or RPM's you state. I have a 17 pitch prop and am wondering if I should go to a 15 as you have. If you don't have the SS model that might be the difference.

[PV]

My experience has been the following. These motors are rated to run at 5000 to 6000 rpm.s When prop'd with an "average" prop of say 17" and getting say, 5200 rpm's it seems a little weak and somewhat lacking in performance. Going down to the next size prop, such as a 15" would seems to give you more rpm's and give you ( in theory) less speed, BUT it appears that that's not what happens. Going down in pitch gives us more rpm's, Say 5800 or so and the motors seems to really wake up on speed and performance. Performance is relative, you know !!!But, my point is this. Get the motor turning as close to 6000 rpm's and I think you will really have a peppy motor you will love. My 2 cents.

[Bruce]

Not that I'm an expert or anything but the experence that I have with the last motor I bought. It would be nice to get several different props, say 5 or so. Go to the lake and give them a try untill you find the one you want. For the kind of money that we shell out for these rigs. Dealers should be more than willing to let you try out a prop or two untill you get the one you want or need.

There is no dought that onece we got the smaller pro on the boat. The motor really came to life.

I think before I went and baought a new moter I would look into differnet props. The Evenrude/Suz is a nice unit I think that I would like the fuel injection over the carbs on the Merc.

Something to think about.


Bruce

[Fred_G]

Pat,

I have the 1700 Angler tiller. It took a while to finally get the correct prop. Started out with a 19 pitch, then went to 17, and finally to 15 before I could get the max rpm's. The 17 would only max out at about 5100 rpm's. The range for the motor is 4500 - 5500 so I wanted to get as close to the top end of that as possible. Sounds like you might want to try a 15 pitch prop and see what happens. Good Luck! Fred

[Bruce]

Pat

Had the exact same prop story as Fred. Only with a 75 HP Merc 4-stroke on an 2000 1775SE.

Mess with the prop before you buy a new motor. Good luck

Bruce

[Fritz]

I guess the grass is always greener on the other side of the fence. :) I have a 2 year old Honda 75, and one of my few regrets is that I did not get the Evinrude/suzuki 70 HP with the electronic fuel injection. The other is that I did not go to a 90 hp because on the Honda, it is the same weight as the 75. But if I could do it over, I would take the Evinrude/Suzuki 70.

[Eric_WI]

I agree. He's going to be disappointed with a carburated 4-stroke after he's owned one with fuel injection.

[Pat]

Thanks guys for the feedback, looks like I need to give the 15" pitch prop a try. I had the same reservations thinking "by theory" less pitch would give up speed, but it sounds like there's a good chance that's not going to be the case. I'll pursue this soon!

[Pat]

Thanks Fred, my manual for the Honda calls for a top end RPM of 6,000. I'm only getting 5,100 to 5,200. Looks like I need to step down to a 15 and give it a try.

[Mr T]

I've never owned either but I can say a 75 won't give you much more top end than your current 70. Go with the 90 if it's more punch your looking for.Just make sure your boat is rated for it.