Merc 3 cyl running 6500 rpm's

Texasmark

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Dec 20, 2005
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Felt like fooling around today so I took the 24XP Ballistic off my engine and put the 21 back on. I only ran it once after I bought it and that was a year ago. Forgot how it performed. Thinking about going to the coast and fishing the shallow brackish lagoons and don't want to ding up the "baby". Additionally will be doing a lot of 15-20 mph running and will be pulling a lot of wake....lotta load on the engine.

Holeshot instantaneous. Only doing 20ish mph at 3200ish so mpg will surely suck, but for the slow running I mentioned, it's perfect as the engine is nice and relaxed under the load....can tell by the way it sounds and responds to throttle changes.

Hammered down on it from about 4000 and the rpm's shot up to 6000 and once the boat got up to speed (caught up with the prop 8) ), 6500 was a piece of cake. Engine sounded sweet, like it wanted more. Backed off a couple of times and goosed it and she just loved it.

I had a mid '80's 4 cyl 85 Merc and it wasn't near as frisky as this 3 cyl........if I only had that 4th cylinder when I'm idling......to stop my clutch dog rattle....which was much quieter with this prop (lighter and less pitch).

So, what's the point of this thread? Don't know. Guess it's for the guy that's worried about a couple hundred rpm's over max rating hurting his engine. I didn't have a tach on my 85 so I don't know where it was running. But since then my Mercs seem to love the high rpm's, like my '89 115 tower WOT'd at 6000 and that's where I ran it .....for 7 years and my son-in-law has been running it there since then. If I can believe the tach on my son's 150 it runs 6000 at WOT and has been doing that since '95.

Mark


Mark
 

WillyBWright

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Re: Merc 3 cyl running 6500 rpm's

The V-6's love 6 grand. Your is stretched to the rev limiter. I'll bet you feel it being tickeled every once in awhile. The inline-4 2+2's snap cranks at about 6200. :^ If it snaps below the second or third cylinder, there's a potentail for it to wind-out wildly in a split-second and grenade the flywheel. :%
 

Silvertip

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Re: Merc 3 cyl running 6500 rpm's

Mark -- it must have been the different plugs!!! 8)
 

Chinewalker

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Re: Merc 3 cyl running 6500 rpm's

I've gotta wind the tar out of my old Mark 30H in order for it to make any power. It's a dog at 6000, but get a prop on it that lets her spin to 6800-7000 and it's a screamer! Yep, a lot of the older inline Mercs like to spin up a bit...
- Scott
 

Texasmark

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Dec 20, 2005
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Re: Merc 3 cyl running 6500 rpm's

Hey Silver, right on :love:

You know it just makes me wonder, just where do these things stop? My 90 apparently doesn't have a rev limiter.

Get this. I bought this rig in Dec '05. It was sold in '02 to the previous owner from whom I bought it. It had a 17" Ballistic SS prop which came on it. (Remember guys, this engine has a 2.33 gearbox and it's on a 17' alum padded bass boat.)

Now if I can easily spin up 6500 with the 21P I can't imagine what kind of rpm's this guy ran for the 3 years he had it......really I don't want to know.

I vividly remember the first time I had it out (with the original 17P prop). Cleared the "no wake" buoys and hammered down on it.....bout broke my neck with whiplash. About 10 seconds later I knew I had a serious prop pitch deficiency. :%

Mark
 

kenmyfam

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Re: Merc 3 cyl running 6500 rpm's

Drag racer eh Mark !!!!!
 

Texasmark

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Dec 20, 2005
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Re: Merc 3 cyl running 6500 rpm's

Well Ken, fish don't bite very often and as I get older my patience gets shorter. My boat is by no means a hotdog, but for what it is I have a lot of fun with it. Most of the time I go out for a couple of hours and spend more time romping than fishing. Since I go on weekdays, the place is pretty much mine so I don't bother anyone with my antics........I don't think d:) .

Mark
 

kenmyfam

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Re: Merc 3 cyl running 6500 rpm's

Long as you have fun Mark. I am not much of a fisherman myself. We do a lot of skiing and tubing and generally blasting about. Enjoy, thats what its all about. I may slip my 17 pitch on mine in the spring and have a bit of fun too.
 

Texasmark

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Dec 20, 2005
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Re: Merc 3 cyl running 6500 rpm's

Sounds like a winner Ken.

Mark
 

kenmyfam

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Re: Merc 3 cyl running 6500 rpm's

I will let you know how I go on. I just wish that the lake was all liquid again !!!!
 
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