max RPM

biggjimm

Chief Petty Officer
Joined
Jul 15, 2015
Messages
403
Is there someplace I can find out what the max RPM for my motor is? It's a 1990 60 hp 3 cyl Johnson on a 17' tracker alum. deep V. I remember when I ran it last year the speedometer on the boat read right at 25 but I dont remember what tachometer read. It has a 13.25 x 17 prop on it & the guy said he put a new prop on as the old one was stolen & he "thought" it was the right prop so I want to make sure everything is fine when I start running it & try to avoid any problems .Thanks .
 

hardwater fisherman

Lieutenant Commander
Joined
Mar 19, 2010
Messages
1,725
I am not 100% sure put probably max rpm should be 6000. I think it should run somewhere around 5500.Or maybe a little more.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
The factory recommended rpm range is from 5000-6000 rpm's. You will want to prop it so that you run it right at the top of that range, or 6000.
 

biggjimm

Chief Petty Officer
Joined
Jul 15, 2015
Messages
403
I'll have to check but I'm thinking it was only turning around 4200-4300 on the tachometer but I can't say for sure until I run it again.
I did notice something today when I had the cover off & worked the throttle it didn't look like the butterflies were opening up all the way & I could manually work the linkage on the carbs & open them the rest of the way. I'm going to pull the cover off the airbox & look at it to see what's actually going on in there & then I'm going to look at the manual & see if maybe something needs adjusted.
I would have thought this boat to run more than 25 mph with 1 person & no gear but maybe not. That was with the speedo on the boat which may or may not be accurate. I'll check it with GPS next time. As soon as I get a chance to get it on the water & see what it's doing I'll let you guys know. Thanks. Jim.
 

biggjimm

Chief Petty Officer
Joined
Jul 15, 2015
Messages
403
Ok, so I took the boat out yesterday & it ran great! It was me & the wife & our two year old granddaughter. The only gear we had was a small cooler with a couple bottles of soda & a bag of ice, a bucket of minnows & a couple rods. 10 gallon fuel cell full & two deep cycle batteries are the only hefty items in the boat. With that load, at wide open it turns 4600 rpm's at 28 mph. The speedometer in the boat said 25 but I know it was running 28 because the CO showed me his radar gun after pulling me over for speeding. Just a verbal warning thankfully. So, I'm a little ways off of the 5500-6000 rpm's that it's supposed to run at. As far as I can tell the prop is the correct size that came on it from the factory. It's 13.25 x 17 & the original owner bought it new & lost a prop but he said the replacement was the same size. He could not remember what rpm's it ran when he had it & he said it had never been messed with as far as the motor goes. I'm going to start a new post concerning whether the carb linkage is working correctly & opening all the way or not as I mentioned above. Thanks. Jim.
 
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