Going to a larger motor?

[Tim Stone WindDancer]

Hi guys, I have always thought about moving up from the old 50 Hp to something with more HP.. Has anyone out there done an upgrade to a larger motor say 70, 90 or even 120? What were the things to do to prepare for this.. Did you have to beef up the transom? What did the extra weight do to your sailing and handling? What did you change to compensate..

Today I have th 2 stroke 50HP Merc at about 205 Lbs.. Considering both 2 and 4 stroke options on the larger motor. The weight goes up 100 Lbs minimum and seems to plateau at about 315 before getting really crazy and doing more than the 120..

Your thoughts would be greatly appreciated

Fair Winds
Tim Stone

[nemo]

There are many threads on this topic to search for in past posts. To get specific feedback you need to state what boat/year you have.

[Tim Stone WindDancer]

Yup you're right.. Mine is a 2000 26X...

[Bobby T.-26X #4767]

this was a good long thread about larger motors:

90hp Outboards

Bob T.
"DaBob"
'02X w/ '04 90-TLDI (14" x 11 pitch)
Dinghy Motor: '06 2.5-Suzuki

[Tim Stone WindDancer]

Wow, 7 pages later and much redder eyes that was a lot of discussion..

Chip, your MEE is showing.. Good Job.. Myself EE but a closet MEE.. (at the end of the day math and physics are the same regardless of pushing water or electrons).

Sounds like the basics are the hull warranty BTW which on the X boats was 5 years.. Stesses and wear and tear..

The Pic on the transom stiffener wasn't clear so if anyone has description to go with Pic that would be really helpful..

One of my questions that really didn't get much play in the thread is does the increased weight of 100Lbs have a pronounced detrimental effect on sailing?

My X boat with my Merc 50 (non-bigfoot) has a considerable amount of rear rake and I do 3/4 on the keel to get a good balance for sailing. Is the larger motor going to make that harder to achieve?

Thanks guys..

Fair Winds
Tim Stone

[Catigale]

Sounds like the basics are the hull warranty BTW which on the X boats was 5 years.. Stesses and wear and tear..

5 years on the hull??? Hmmm....

Ive got the Merc Big foot 50 on the back of my but my skills (or lack thereof) are what limit how my boat sails..

I dont think you can quantify how the sailing is impacted from 50 to 75 to 90 on up in a meaningful, useful way.

[Bobby T.-26X #4767]

The Pic on the transom stiffener wasn't clear so if anyone has description to go with Pic that would be really helpful..

the inside of the transom motor well is a 1/4" aluminum plate that i suggest you fabricate yourself. that is, purchase the material, and cut/sand yourself to fit exactly as pictured. you can paint white so it won't be noticed.

then, inside the rear end (accessed via the rear berth) is basically a "plate" of sorts that serves as a large washer. fairly simple to create.

finally (not pictured) is the "pad" on the outside rear which is either the one you are currently using, or one that the installer has for the new outboard motor. it is usually 1/4-3/8" and made from a "poly" material, although some have used aluminum and painted white.

regarding the existing holes in the transom vs. new holes required for mounting...
i was able to use all existig holes from my Suzy 50 for my Tohatsu 90. if you cannot, try to fill with an epoxy/resin material purchased at West Marine (or boat shop).

PM me with your email address if you want outside pics of my transom.

Bob T.
"DaBob"
'02X w/ '04 90-TLDI (14" x 11 pitch)
Dinghy Motor: '06 2.5-Suzuki

[trumpetguy]

My 2005 M came with a Honda 50 that was not enough to get the 20 MPH I wanted. Even with several prop adjustments 14 mph was the max at WOT, and it was really loud. I was able to trade for a new Suzuki 70HP and wow what a difference. I am still in the break-in period so have not been WOT yet. I am cruising at 16MPH (GPS) at 4000 RPM. That is without ballast and a light load. The dealer put a "break-in" prop on, which restricts my RPMs to 4200, and I am going to get a 13.75' X 13 installed at my 20 hour service. Can't wait. The Suzi is a sweet engine...quiet, starts like a car, and fuel efficient.

The only transom mod we made was spacers to incline the foot in toward the boat. This was per Todd at BWY, and my dealer here in Pensacola agreed that was a good thing to do.

[Frank C]

... The only transom mod we made was spacers to incline the foot in toward the boat. This was per Todd at BWY, and my dealer here in Pensacola agreed that was a good thing to do.

Yep, that transom wedge is a standard feature for installing outboards on the Mac.

That 13.75x13 is a stock prop from Suzuki. However, I think you may prefer an 11-inch pitch. Ask your dealer if he can install a used one first to see if you reach the recommended rpm range ... if it can't reach ~5500 rpms with ballast empty, it will be lugging. Strange as it might seem, most Macs under 90 hp - from Bigfoot 50s to Suzuki 70s - all seem to do better with an 11-inch pitch.

[Dimitri-2000X-Tampa]

Not in my case Frank. When I bought my boat, it had the 14X11 and wouldn't go much above 5000 RPM at WOT. I replaced it with the 14X10 and got much better performance, and much better RPM too, around 5800.

Perhaps the 14X11 is good in the 60-90 HP range.

I might move up to a bigger motor in 2-3 years, just can't see taking a big depreciation hit for a motor that is running great. Plus the fact that it is a 4stroke increases the life of the motor quite a bit over a 2stroke IMO.

[delevi]

Very strange. Mine came with a 14x13 and got up to 5400 rpm and maxed out over 20 mph. I dinged up a prop and had it sized down to 13.5x13 via rebuild and got slightly better performance. I borrowed a 14x11 from the dealer and had way too much RPM 6200 and maxed out at 17.5 mph. Having dinged up the prop yet again on the Napa River, I now had it rebuilt to a 13.25x13. I think this one will be ideal, but haven't tested it yet. I'm really surprised by all the 11 pitch or less props being used. For my setup, it would only work well in high altitude.

[Frank C]

I think the ETEC is a different animal. They swing larger props and seem to have more torque. Even the 70 hp Suzuki is usually happier with less than 13 pitch.

[Moe]

They're all different animals, i.e. different gear ratios, and in the case of the DF50, much higher maximum rpm. Member Robert once posted recommendations for each, but the forum software lost it.

--
Moe

[Terry]

Trumpetguy wrote:

My 2005 M came with a Honda 50 that was not enough to get the 20 MPH I wanted. Even with several prop adjustments 14 mph was the max at WOT, and it was really loud.

This is not the first time I have read something like this and it always makes me wonder. There are likely several variables that are affecting the performance, any one, or all could be the culprit. I have an '03 M with a Honda 50 and have seen 19mph on several occassions, usually at the beginning of the season with a fresh waxed hull and lighter load. I have noticed that towards the end of a sailing season I am lucky to see 13-14 mph, but after haul out the dirty hull bottom and all the crap I take out to store in the garage pretty much explains it. Next spring I am going to pay closer attention to what I put back in the boat and perhaps seperate all the stuff I carry around for extended cruising from the daysailing requirements. This should exceed 100lbs then I will take her out for a run solo without the Admiral and see if I can hit the 20mph speed at WOT. The times I hit 19mph my wife was in the boat with me and I was likely carrying a few extra supplies & gear. I am quite confident that under more ideal conditions 20mph is doable. When the company advertises 22mph they are also under ideal conditions so I will do the same. I am not convinced that anyone really needs those big heavy engines they are more likely a want. If I could go back the most I would upgrade to is an e-tec 60 that swings a 14" prop with the lower geaar ratio and only weighs a bit more than a Honda. For now the Honda works just fine and will have to do until it dies.

[Bobby T.-26X #4767]

When the company advertises 22mph they are also under ideal conditions so I will do the same.

their ideal conditions: 50hp, absolutely no supplies, 3 gallons of fuel, no water or effluent, 150# captain, no passengers...

I am not convinced that anyone really needs those big heavy engines they are more likely a want. If I could go back the most I would upgrade to is an e-tec 60 that swings a 14" prop with the lower geaar ratio and only weighs a bit more than a Honda.

to each his own...different strokes for different folks...
- a honda is a carburated 205#, old tech motor
- an Etec 40/50/60 (same powerhead) is new tech, injected, 240# (+) motor. so, the Etec 60 is a computer tuned 40 (& visa versa)
- Etec 75/90 (same powerhead) is 320#

the larger motor works for me as i go 60 miles across the blue pacific, directly into a headwind, to Catalina Island in my heavy loaded X for the weekend.
I wanted the extra power to get me on plane at 18-20mph (top speed is 25+) to make that long run in 3 hrs.

my Tohatsu 90 is only 70# (+/-) more than my previous Suzuki 50hp which could only manage 15-16mph WOT under similar loads.

it's worth it to me for my needs.

however, if it was primarily used on a landlocked lake, i might consider a 25hp.

Bob T.
"DaBob"
'02X w/ '04 90-TLDI (14" x 11 pitch)
Dinghy Motor: '06 2.5-Suzuki