Questions about a new motor for an oldie (1985)

[SeaFare]

I've decided to refloat my boat (seriously) which is a 1985 18' model. Its original motor (a 65 Suzuki) is quite dead and I don't mourn its passing, except for the cost of replacing it!

I would like to put a new 4-stroke Honda on it. Here's my problem - my boat seemed quite doggy with only two people and some fishing gear on board, so I was thinking of going to a Honda 75 hp. However the boat is rated for a 70, which means the dealer cannot install it for me. That's not a problem, but I'm worried that the new motor may be too heavy for the transom and that I might be overpowering the boat. I called the C-Dory manufacturer, noting that new 19' C-Dorys are rated for up to 100 hp. They could not really answer my questions as to whether there had been any structural change in the transom from the older models to the newer, and generally could not advise me whether the 75 Honda would be a good decision.

The leap in weight (more than 100 lbs heavier than the 65 Suzuki 2-stroke) seems to be about par for any new 4-stroke of comparable hp.
The other option would be to drop to a lower hp, (for a Honda that would be a 50 hp) and I'm not sure the performance would be that good.

Does anyone have some experience or helpful thoughts on this? I'd appreciate any comments you might have. Thanks

SeaFare

 

[starcrafttom]

if you go with the 75 honda get the 90 instead, same motor and same wiegth so you might as well get the extra power . As far as lighter motors there are lighter 4 strokes then the honda and the e-tec is even lighter then that.

 

[tsturm]

I've decided to refloat my boat (seriously) which is a 1985 18' model. Its original motor (a 65 Suzuki) is quite dead and I don't mourn its passing, except for the cost of replacing it!

I would like to put a new 4-stroke Honda on it. Here's my problem - my boat seemed quite doggy with only two people and some fishing gear on board, so I was thinking of going to a Honda 75 hp. However the boat is rated for a 70, which means the dealer cannot install it for me. That's not a problem, but I'm worried that the new motor may be too heavy for the transom and that I might be overpowering the boat. I called the C-Dory manufacturer, noting that new 19' C-Dorys are rated for up to 100 hp. They could not really answer my questions as to whether there had been any structural change in the transom from the older models to the newer, and generally could not advise me whether the 75 Honda would be a good decision.

The leap in weight (more than 100 lbs heavier than the 65 Suzuki 2-stroke) seems to be about par for any new 4-stroke of comparable hp.
The other option would be to drop to a lower hp, (for a Honda that would be a 50 hp) and I'm not sure the performance would be that good.

Does anyone have some experience or helpful thoughts on this? I'd appreciate any comments you might have. Thanks

SeaFare

I would go with a Yamaha. :wink: (better cold water performance)
My 1990 22 Cruiser is only rated for 90hp. I put a 100 Yamaha on it in 2002 or 2003, the same boat is now rated for 115hp I believe. The older C-Dorys were built one or two at a time with more attn to detail. I dont think you will have any problem hanging a 4 stroke on there. :beer Call the guys at C-Dory?

 

[SENSEI]

Byrdmans 18 with a 50 Suzuki
it works well

 

[Sea Wolf]

SeaFare-

I think the 18 is different than a 19 or a 22, how much I don't know. We'll have to get Byrdman to measure his boat to see, and I'm sure he's got some definite ideas about the proper power needed for the boat.

The 19 and the 22 are the same boat, hullwise, with just 3 feet removed from the 22 to get the 19. They seem to require the same hp to get equal performance.

How much the 18 approximates being equal in hp requirements and handling capability I don't know, and the present factory probably doesn't either. So we'll hope Patrick (Byrdman) or some other 18 owner can help us out here. The other alternative is to PM or email Ben Toland who I think was involved in manufacturing the 18 and may have even been it's designer. Oldgrowth Dave can help you out with that contact.

I love my 90 hp Yamaha 4S EFI engine, but it does weigh 369 lbs. The Evenrude e-techs are very light for their hp, but are basically direct injected modified two strokes. One of our members* had some serious problems with cold weather performance from his e-tech. Their hp/weight ratio is very enticing, though!

Joe.

*Tom Brady, boat: Bidarka.

 

[Doryman]

I would go with a Yamaha. :wink: (better cold water performance)

I like my Yamahas, but did not know that better cold water performance was another advantage -- is this just in comparision to the E-tek or in comparison to other 4-strokes also?

Warren

 

[tsturm]

I would go with a Yamaha. :wink: (better cold water performance)

I like my Yamahas, but did not know that better cold water performance was another advantage -- is this just in comparision to the E-tek or in comparison to other 4-strokes also?

Warren

I used a 90 Honda 4 stroke for two winters, before switching to a Yamaha F-100. My own experience is what I am basing my statements on! :beer Other's mileage may vary :wink:

 

[CAVU]

I would think Oldgrowth Dave could shed some interesting light on this subject. He stretched his 16 to 18 feet. If he doesn't pop up here you might shoot him a PM.

 

[Sea Wolf]

I would go with a Yamaha. :wink: (better cold water performance)

I like my Yamahas, but did not know that better cold water performance was another advantage -- is this just in comparision to the E-tek or in comparison to other 4-strokes also?

Warren

I used a 90 Honda 4 stroke for two winters, before switching to a Yamaha F-100. My own experience is what I am basing my statements on! :beer Other's mileage may vary :wink:

The performance of any good EFI engine will outdo an outdated carbureted engine virtually every time.

That's the reason we were criticizing the Honda 90's carburetered design which was only finally changed in the 2007 models with the general engine re-design!

Yes, Oldgrowth Dave will have much to say about this CD-18 repower!

Joe. :teeth

 

[SEA3PO]

Boy Joe is sure right on there..... I would trade in my twin Yamaha 40's for a fuel injected set in a heartbeat if they wouldn't kill me with the difference... I was docked behind one of those new 90 Honda fuel injected motors in Santa Barbara and was impressed with how easy it started and ran...so smooth and quiet... from cold start to underway it was flawless.

My ole 40 hp Yamaha's have to go through a complete choke cold start...then finally once their warm they might idle...and might not..



Joel
SEA3PO

 

[tsturm]

Boy Joe is sure right on there..... I would trade in my twin Yamaha 40's for a fuel injected set in a heartbeat if they wouldn't kill me with the difference... I was docked behind one of those new 90 Honda fuel injected motors in Santa Barbara and was impressed with how easy it started and ran...so smooth and quiet... from cold start to underway it was flawless.

My ole 40 hp Yamaha's have to go through a complete choke cold start...then finally once their warm they might idle...and might not..

Joel
SEA3PO

Sounds like you need to adjust some carbs! :wink:

 

[tsturm]

I would go with a Yamaha. :wink: (better cold water performance)

I like my Yamahas, but did not know that better cold water performance was another advantage -- is this just in comparision to the E-tek or in comparison to other 4-strokes also?

Warren

I used a 90 Honda 4 stroke for two winters, before switching to a Yamaha F-100. My own experience is what I am basing my statements on! :beer Other's mileage may vary :wink:

The performance of any good EFI engine will outdo an outdated carbureted engine virtually every time.

That's the reason we were criticizing the Honda 90's carburetered design which was only finally changed in the 2007 models with the general engine re-design!

Yes, Oldgrowth Dave will have much to say about this CD-18 repower!

Joe. :teeth

Both my Honda & Yamaha are / were Carbeureted. Hopefuly the later FI models of either have addressed this cold blodded concern :beer

 

[SEA3PO]

I just looked online and see that the Yamaha 40 is still carbureted and the 50 is fuel injected..... plus it has 4 cylinders the 40 has 3 cylinders
The Yamaha sells for just over $5 K

Joel
SEA3PO

 

[CAVU]

Joel,
I think you are pulling our legs-how does one get a "cold start" on anything in Santa Barbara?

 

[SEA3PO]

Ok....make that a Chilly start.........

The fog rolled in and that is kinda cool....

Joel
SEA3PO

 

[Sea Wolf]

I would go with a Yamaha. :wink: (better cold water performance)

I like my Yamahas, but did not know that better cold water performance was another advantage -- is this just in comparision to the E-tek or in comparison to other 4-strokes also?

Warren

I used a 90 Honda 4 stroke for two winters, before switching to a Yamaha F-100. My own experience is what I am basing my statements on! :beer Other's mileage may vary :wink:

The performance of any good EFI engine will outdo an outdated carbureted engine virtually every time.

That's the reason we were criticizing the Honda 90's carburetered design which was only finally changed in the 2007 models with the general engine re-design!

Yes, Oldgrowth Dave will have much to say about this CD-18 repower!

Joe. :teeth

Both my Honda & Yamaha are / were Carbeureted. Hopefuly the later FI models of either have addressed this cold blodded concern :beer

My 2005 Yamaha 90 4-Stroke EFI motor starts and runs just like a first class new car, regardless of the weather or any other conditions.

It's electric smooth and quiet as well.

It replaced a 1987 Evinrude 90 2-stroke smoker that was pretty much indestructable, but of another era technologically.

Comparing the two is likening a miller's waterwheel to a hydroelectric plant.

18 years of technological improvement ='s light years of difference!

Joe. :teeth

 

[SeaFare]

I appreciate all the comments written in response to my post about repowering my 1985 18'. A number of you mentioned "Oldgrowth Dave" and "Byrdman", and one mentioned Ben Toland who might have been involved in the design and construction of my model boat. I plan to follow up with contacts to these people if I can.

I probably now have more new questions from your suggestions, but they represent considering other options. I'm definitely on a learning curve and appreciate how helpful it is to hear the discussions.

Thank you all - what a great source of information The C-Brats provide.

Dee
SeaFare