Worth it to upgrade to an 8hp engine?

AndreInPortland

AndreInPortland

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Mar 31, 2019
64
Catalina 22 12640 Rose City Yacht Club
Hi all,

The current on the Columbia river is really strong in the spring time, and the Yamaha 2-stroke 6hp I have on Avalon right now barely does the job when heading upriver against the current. I'm considering upgrading to a 4-stroke 8hp outboard so I can make better headway, but I had a couple questions.

  1. Would a newer 4-stroke 6hp significantly outperform my 25 year old 2-stroke 6hp, thus I don't need to pay the extra $$$ for an 8hp?
  2. My existing Yamaha 6hp weighs 59lbs. It looks like the 8-hp engines weigh in around 85lbs. Does this mean I'd need to upgrade my motor mount as well? I've attached the best picture I can find of my existing motor mount. (Let's put aside my comfort and convenience for the moment and assume I can handle the additional 30 lbs when lifting the motor up on my current mount.)
  3. Anything else to consider that I'm not asking about?
Thanks!

Andre
 

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pclarksurf

pclarksurf

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Jul 13, 2015
919
Catalina 22 #2552 2252 Kennewick, WA
Fellow Columbian-- not sure what your average current is down south-- but up here I've got a steady 4 KN.. 2006 honda 5 is all I could ever use. I think the more efficient 6 will do you just fine and remember hull speed is hull speed ... you start to add weight / bulk and inneficiency at some point.

File_000 (4).jpeg
 
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AndreInPortland

AndreInPortland

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Mar 31, 2019
64
Catalina 22 12640 Rose City Yacht Club
Dang, 4 knots! I don't think we see above 3 knots here, and that seems pretty fast to me. Since you seem to be getting along just fine with a 5hp engine, it's making me think that my old engine is just horribly inefficient and I'll be fine with a new 6hp.
 
pclarksurf

pclarksurf

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Jul 13, 2015
919
Catalina 22 #2552 2252 Kennewick, WA
Yep, I'm just below the last free running section of the Columbia (Hanford Reach) and well above McNary-- so technically a lake but she can run pretty hot depending on what the Corp of Engineers is up to. The NOAA chart stops right on top of my favorite spot...

My guess is you'll be in good shape-- and your back will appreciate you
 
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Hunter216

Hunter216

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Sep 22, 2018
1,869
Hunter 216 Kingston
AndreInPortland said:
Dang, 4 knots! I don't think we see above 3 knots here, and that seems pretty fast to me. Since you seem to be getting along just fine with a 5hp engine, it's making me think that my old engine is just horribly inefficient and I'll be fine with a new 6hp.
Click to expand
Don’t forget it’s not just the hp rating. You might also consider prop size, pitch, number of blades etc. Maybe all you need is a different prop???

Of course that’s not nearly as exciting as a new motor!! ;)
 
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H

Hardhead

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Apr 11, 2017
571
Catalina C22 Solomon's Island, MD
Hunter216 said:
Don’t forget it’s not just the hp rating. You might also consider prop size, pitch, number of blades etc. Maybe all you need is a different prop???

Of course that’s not nearly as exciting as a new motor!! ;)
Click to expand
I agree - the right prop can make a big difference. If you don't go for the new motor, maybe try a higher or lower pitch, etc.
 
J

john renfro

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Jun 4, 2004
35
-catalina -22 fresno, calif.
I assume you are running wide open, Before you start swapping props, think about getting a small cheep tachometer.
A Tiny Tach ( or some other) sells on ebay for about $10.00, easy to use, check for engine over/under speed. If over speed, you can get a higher pitch to move more water and slow engine down to proper speed. If you aren't making max rpm, you can use a lower pitch to speed the rpm. More hp by itself doesn't necessarily bring more speed.
 
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