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25hp carb to 30hp carb on 1999 Johnson

V

valvebounce

Regular Contributor
Would the revs go above the WOT,or would the extra power be more torque?
If a car or bike engine is given more power,it is converted into more revs,but more revs on an outboard have a limitation.
Without a change in gear ratios,wouldn't a power uplift be over revving the motor?
 
That's right. You shouldn't exceed factory "red line" .....although there is a "margin of protection" on recommended rpm, you need to adjust propeller. As you may know, by exceeding recommendations at WOT, you might not immediately blow up the motor, but you will shorten it's effective life.
 
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Yea,same guy,does he know it takes a lot more than a caburator to make a 30 out of a 25,for a gain of maybe two mph?
 
Rwbutler said:
cylinder and crankcase look it up yourself
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I will help you out here. The 32 cid blocks are identical in the 20-35 hp motors. No difference in stroke ,porting or anything else. Most of it is the carb. The 30 hp is just a prop rated 35. Little tid bit for ya
 
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About 50 or 60 years ago there were rumors of magical carburetors that could get up to 200 miles per / gallon on your grocery getter.----Carburetors still appear to be a mystery today.
 
racerone said:
About 50 or 60 years ago there were rumors of magical carburetors that could get up to 200 miles per / gallon on your grocery getter.----Carburetors still appear to be a mystery today.
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Welll then you tell us the difference! I just had a 25 and 30 hp motor in my shop side by side. SO please enlighten me.
 
flyingscott said:
I will help you out here. The 32 cid blocks are identical in the 20-35 hp motors. No difference in stroke ,porting or anything else. Most of it is the carb. The 30 hp is just a prop rated 35. Little tid bit for ya
Click to expand...
So why dont they have the same part number and price?
 
flyingscott said:
I will help you out here. The 32 cid blocks are identical in the 20-35 hp motors. No difference in stroke ,porting or anything else. Most of it is the carb. The 30 hp is just a prop rated 35. Little tid bit for ya
Click to expand...
So,what else did ya find that was different on a 99 25and30?or didnt you look?
 
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