I have a 1989 175 merc black max .It runs great but would like to get more out of it. HELP!!!
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I have a 1989 175 merc black max .It runs great but would like to get more out of it. HELP!!!
g- force exhaust, shaved heads, bigger carbs, sportmaster gearcase, differetn prop,
Hay d - what does it run? I have a 150 that runs over 70 or so - bone stock with a 21 pitch cleever- looking at running a 26-28 chopper.
Its on 18.5 concord open bow. It does 60mph on gps with 21in prop at 5800rpm
I had a motor very similar to yours ('88 200 Black Max). I am not sure what the differences are between the 175 and 200, but my guess would be carbs. Find out the differences, this will point you in the right direction.
First and foremost, prevent further problems by strengthening your gearcase so you don't destroy it (I have done this twice, not cheap $$$). Send it to Bob's in FL to have a nose cone/low water pick-up put on (Bob's gives the best water pressure in my opinion, VERY IMPORTANT). Also have them install a heavy duty bearing carrier. Run Mercruiser high performance stern drive lube in the gear case.
Add solid motor mounts if you don't already have them. Top and bottom.
Add a jack plate next. I like CMC. This will give you set back and motor lift. Run the jack plate high enough so that you get no less than 10 lbs of water pressure (I fried a motor by not paying attention, not cheap $$$). WATCH YOUR TEMP GAUGE! If you are running at least 10lbs. and your motor still heats up quick when making speed runs, take the thermostats out of the heads and run stainless steel washers in the stats place. This will allow for more water flow.
If everything checks out okay with the above steps, you should see at least 5 mph, maybe more like 7.
Not satisfied there, next and by far, the best bang for the buck is a relieved exhaust system. Remove the lining in the mid section drill five or six (3/8") holes just above the gearcase on each side, and put a g-force exhaust tuner in it. This will net you 20-25hp.
If you are not satisfied with that, I would do all of the following at the same time. Shave 50 Thousandths off the heads, put high performance reeds in it, and either cross drill the intake or add and aftermarket intake. Again make sure the carbs are not your limiting factor which I suspect they may be. With the heads shaved, you will need to run a mix of Avgas/race gas and 92/93 octane. Also run a synthetic lubricant. I like Klotz KL-333. Mercury is also good. Snappertapper and others like Amsoil. Any should work. If you do all these mods, your rpm band will jump so I would recommend disconnecting the oil injection. Mix oil at 32:1.
Last but not least is the prop. Run a 3 blade round ear prop. You need lift. Pitch would depend on what you do to the motor. Good Luck.
Thank you for the info
Hey Dval i think you should buy my merc 94 200 xri with nose cone and low water pickup, to go faster http://free.***boat.net/ubb/biggrin.gif