20 hp hop up

[brandong]

i have a 1974 25 hp johnson i wna get more power out of it on the top end power how would i do that

 

[Bob_VT]

Re: 20 hp hop up

I moved your post.

PLEASE read the forum rules and do not bring up and answer old posts from the archives.

You really can not hop up an older motor

 

[Chinewalker]

Re: 20 hp hop up

I agree - not much you can do to the 25hp, as it is already pretty well "hopped up" being that it started it's 22-cube lineage as an 18hp in 1957.

 

[82rude]

Re: 20 hp hop up

the best you can do for your motor is to make sure your turning the proper rpm at wot.

 

[sschefer]

Re: 20 hp hop up

What Chinewalker is telling you is 100% true. The motor is pretty much maxed out but remember, it's a retail item and has to meet a certain level of durability so it's not completely maxed out yet. There's still a few ponies waiting to be unleashed under that hood. Get a copy of the two stroke tuners handbook and give it a read. Here's the a link to it that I found: http://www.vintagesleds.com/library/manuals/misc/Two-stroke Tuner's Handbook.pdf Anybody worth their salt in the two stroke performance world knows about this book.

 

[5150abf]

Re: 20 hp hop up

Welcome to iboats.

All good advice advice, just make sure it running correctly and that is really all you can do.

I am sure there are all kinds of hop up stuff you can do, shave the head, port and polish ect, but all that stuff takes away from longevity and the motor is already 38 years old and probably pretty well used I would imagine.

Not to mention the 2-3 extra horse you would get out of it would really go unnoticed, to get a real improvemnet in performance you would need to find alot more that a few horse.

If this is a spare engine you just wnat to play with, why not, but if it is your only engine and you will be off the water if you muff it up then I would leave well enough alone, do a decarb and clean the carb good and get out on the water.