1981 merc 200 performance

[smokeonthewater]

I can say this, when merc went prop rated the 140 became a 115... That's a 21% reduction.

[THEFERMANATOR]

Originally Posted by smokeonthewater

I can say this, when merc went prop rated the 140 became a 115... That's a 21% reduction.

johnson/evinrude did the same in 85 when they started propshaft rating. yamahas 220 excell became there 175. also keep in mind they could be +/- 10% of the rated hp and still be legal. like how yamahas 200 and 225 4 strokes were the same exact engines except for decals when they 1st came out. they didnt get in trouble because they both made roughly 205-210 hp which was within the 10% hp allowance, but it was frowned upon when it was discovered they were charging $1000 more for different decals.

[jamesbalog]

the johnson was an 88 so it was prop rated

thanks for the explanation

[THEFERMANATOR]

Originally Posted by jamesbalog

the johnson was an 88 so it was prop rated

thanks for the explanation

Yep, you swapped from a 175 to a 175, so performance will be about the same. But like you found out, the 2.4L MERCURY is ALOT better on fuel than the old OMC crossflow was. Reprop to a stainless prop, and let it turn up to at least 5300 and it should do a bit better performance wise. And take care of that 2.4L MERC as it is a good engine.

[RidgeRunner]

Most folks don't know it but the old 2.4L 200's and 175's were chrome bore motors.. The chrome isn't the same chrome as what is on your bumper of your pick-up truck. This chrome is a chemical process essentially making the bore very hard. One thing that the chrome bore 200 did not like was being lugged around. Lugging the motor, ie. tuning the setup so that the motor is not in the recommended WOT rpm range, generates additional heat and could lead to pre-detonation. Translation- Certain death to an old carbed 2-stroke.. They didn't like heat because heat could cause the chrome to start to give up and flake off the bore.
Keep the carbs clean too, it should last a while if you follow the rules. LOL! Performance isn't bad for such a load, your using it to its potential..

[draglink]

you might need to re-prop. I have about the same motor. '80s 2.4 200. I turn it 6100-6300 WOT depending on the chop. Motor wants to turn more! I bump 50mph, fastest I have seen on GPS is 53

[RidgeRunner]

I like 5800 RPM. Apparently so does Mercury because at least two of my motors have a 5800 limiter. Draglink- Funny you should say that the motor wants to turn more rpm, they really are a lot happier winging it up high, it is leverage and gearing.

[garbubba]

I've run a 1994 2.5 liter merc 200 for years. I use a stainless 19 pitch prop, WOT is around 6k & top speed about 45mph by gps. I've switched props in the past, & this one seems best.

[bgreene]

Look forward to your #'s after you switch props........

Also, make sure it's rigged high enough on the transom.
Many boats are run with motors lower than actually needed.

[reelapeelin]

Originally Posted by RidgeRunner

Most folks don't know it but the old 2.4L 200's and 175's were chrome bore motors.. The chrome isn't the same chrome as what is on your bumper of your pick-up truck. This chrome is a chemical process essentially making the bore very hard. One thing that the chrome bore 200 did not like was being lugged around. Lugging the motor, ie. tuning the setup so that the motor is not in the recommended WOT rpm range, generates additional heat and could lead to pre-detonation. Translation- Certain death to an old carbed 2-stroke.. They didn't like heat because heat could cause the chrome to start to give up and flake off the bore.
Keep the carbs clean too, it should last a while if you follow the rules. LOL! Performance isn't bad for such a load, your using it to its potential..

Vic...ya mighta just diagnosed another 2.4 failure we know about...I never felt I was gettin' it all...