What is the most a merc 200 should tach out at?

[joemechanic69]

I just picked up a 1988 checkmate eluder that has a 1988 merc 200 carb motor on it. Previous owner says it was rebuilt a few years ago. The heads have been milled, its got a nose cone, low water pickup, and the mid has been gutted. It has a 6" jackplate, the middle of the nose cone bullet is even with the pad right now. . It is under propped right now at a 23 pitch stainless 3 blade prop. She was still accelerating hard when I off throttled at 5500. My question is what is the highest my motor can tach out at safely? Does anyone have a good prop recomendation? Any help is greatly appretiated.

[Capt.Insane-o]

7k is generally the cut off with cast pistons. A lot of factors in that, the two most important are timing and carb jetting, let alone proper fuel delivery and cooling system health. 6-6500 is perfectly safe.

[Raceman]

The boat will run faster on top end, use less fuel, and the engine will last longer if you prop it to turn a max of 5800 to 6000. There's NO REASON to turn the engine any harder than that UNLESS you like the stronger acceleration and are willing to sacrifice the slight loss of top end and other factors to get it.

[Wizard]

Agree I would prop it to 6200. That is a good, long life RPM for that motor. I'd think a 25p Trophy Plus would be a very good prop for your combo. It should turn over 6,000 when light and by yourself and in the high 5,000s when loaded with people and beer.

[RLP]

6,000 rpm

[dhoday]

The more RPMS you turn the shorter the lifespan
6000 gives a long lifespan
7000 cuts the life in half

[dt63vette]

Just for reference: My 1989 Merc 200 carb (bought new), did many years service on a 1985 Checkmate Enticer 16.6 ft. With a lwp, 10 in jack plate, and a 26 chopper it ran 6600 rpm's at WOT. It nows serves faithfully on a 24 ft. tritoon, and is propped to turn 5800.

Great engine, still runs like the day I bought it, and it has never been apart. Lucky I guess!!!

[specboatops]

I had a 1994 MErcury 2.5 200 EFI Sitting on the back of my Gambler SuperSport, running a 26 Trophy it would spinn right to 6400 and seem to really like it there, it would fire up right away, and idle up and down the river ALL day without loading up a bit.

Man I kinda miss that motor................

Chris

[afr]

i dont know whats special about my 2.5 but they told me im good up to 8600

[AirRide]

i dont know whats special about my 2.5 but they told me im good up to 8600

Really? Cool beans. I bet it will turn more. See if it can crack 10,000. Get back to us.

[afr]

Really? Cool beans. I bet it will turn more. See if it can crack 10,000. Get back to us.

i forsure will i also got a 10,000 rpm tach thats comming with a recall
so there wont be any guessing

[bigtis]

, use less fuel,

5800 to 6000.

I've found on 2.0's and 2.4's the best fuel economy on a boat in the 700-1200lbs range would be to prop it 64- 6600 lite load. 5800-6K loaded is too much prop, and 7K is too short of a prop.. This is all based on fuel economy though, and not lifespan.

Really? Cool beans. I bet it will turn more. See if it can crack 10,000. Get back to us.

my 2.5 200 EFI will make on average with a 24-26 on 1.87's right around 8850-9100 in the 1/4. my drag racing partners 200 EFi has made 9675 RPM on 1.87's with a loose 22 in the 1/4.

[racervboat]

Yeah keep it around 6000 rpm and god is great beer is good and people are crazy.

[KonaKustoms]

6000 to 6300 will last forever with good impeller and gas/oil no cheepo walmart oil ok

[Raceman]

The "how hard can it turn and live" discussion comes up around here from time to time. The thing that it seems like a lot of people lose track of is............... more RPM doesn't necessarily mean more speed. In most cases with stock or near stock fishing type Mercs, it USUALLY means less. I've NEVER SEEN a boat with a stock 175/200/225 that was pitched to turn 6500 that wouldn't run faster if it was pitched to only turn high 5's (assuming good blades in both cases). Even the high perf motors like the 260's and 280's will turn a LOT MORE pitch than people realize, and the only reason to scream any of this stuff is for acceleration. If top end is the priority, pitch is the way to go.