Outboard size for MFG 19?

[SilentPower]

Hello guys,

I'm pretty much new here

Just bought a MFG 19 (LOA -19, 1600 lbs, LWL-17)

It has an outboard mount but no engine.

So what would be a good motor to get to make sure I can do my hull speed on something like Great Lakes?

I was reading different posts, got some ideas, don't want to go overboard, but I want to be able to do my hull speed (5.5kts?) even in 2-3 footers (if possible).

I'm thinking and looking at 4 HP 4 strokes like Nissan or Mercury, they seem to be the same engine but I like Mercury better for some reason.

Few more questions, what my fuel consumtion is going to be like?

Being new to sailing, I'm I correct to assume sailing is pretty much limited to 5.5 kts or is it possible to go a little faster?


Thank you

[sailingdog]

The Nissan, Tohatsu and Mercury are actually all the same engine, all made by Tohatsu IIRC. Fuel consumption really depends on the speed you're running the boat at. Most sailboats are going to be limited to their hull speed, which in the case of a boat with a 17' LWL is going to be about the 5.5 knots you mention—anything faster than that will take a considerable increase in power and run the fuel consumption rate through the ceiling.

The biggest problem you'll probably have, especially in 2-3 foot or heavier seas is the outboard's prop coming out of the water and ventilating... Makes the outboard pretty useless. Make sure you get a long shaft or extra long shaft model.

[SilentPower]

Thank you.
So I'm thinking 4 or 5 hp? Not sure which one, I'm thinking with 4 I might not be able to hit my hull speed..

Will my fuel consumption would go down using 5 or 6 hp instead of 4?

Appreciate any help

[TohatsuGuru]

The 4 is actually a 6 hp with a reduced flow carburetor on it. So, worse case is that you buy the 4 and then buy a 6 hp carb if you need more power.

[SilentPower]

Makes sense, thanks for the tip.
Do you know if I can buy a carb from a delaer or is that only DIY option
Do you think I can hit my hull speed with 4hp 1600lbs + 500 in people and gear?

[timebandit]

Personally I would go with a 8hp.

A little more expensive, a little heaver but two cylinders.

Waaay smother.

I have two.

One a Honda 7.5hp four stroke and a 8hp Yamaha two stroke.

Either one will move my Mac-25 at over 6 knts. at less than 3/4 throttle.

My boats happy speed is about 5 knts. or about 1/2 throttle on either engine and at that speed both burn about 1/2 gallon an hour.

I prefer the two stroke because no matter how hard I try and no matter what position I place the four stroke in the truck when trailering it still leaks oil.

Some of the lakes no longer allow 2 strokes so I drain the 4 stroke of oil and refill at the lake and drain again at the lake. No big deal it only takes about a quart it is just a pita.

The boat must weight around 3,000 lbs. when loaded.

Rick

[sailingdog]

A Mac 25 is a much bigger boat. A 7.5 HP or 8 HP four stroke is an awful lot of weight to be hanging off the transom of a 19' sailboat. I would highly recommend checking with the outboard motor mount's manufacturer, if you know who made it, and see what the specifications for it are. Many were designed for the much lighter weight two-stroke outboards, and will generally need you to downsize the engine if it is a four-stroke, since they're often considerably heavier than their two-stroke counterparts.

[SilentPower]

Thanks,

The mount is a regular 10 hp mount, so I'm pretty sure 4-8 hp 4 stroke is safe.

I think 8 hp is much more than I need.
The question is 4,5 or 6

[chucklesR]

If money isn't the issue go with the 6hp, you won't have to run it at full throttle most of the time which increases engine life over a 4hp running full out. It'll also be quieter.
Just because the mount is for a 10hp doesn't mean your boats transom is designed to hang a 10hp there - you are wise to stay low or at least to look up the specifications prior to buying any engine. Then once you know the weight and thrust limitations go shopping from there.

[TohatsuGuru]

The 4 would be pushing it's limit at a 2000 lb load. Depending on your expectations that might be enough. Personally I am a believer in more hp for the same weight and as you are at the max limit for what a 4 can do ( 1 hp for 500 lb )....The 6 is almost certainly the better choice. Carburetors are available from any dealer that you get the engine through. It actually costs less to get the 4 and buy the 6 carb than to buy the 6. However, the 4 has an integral tank where as the 5 and 6 have a seperate fuel tank and line. I don't think you would be wrong to go either way if you choose to go Tohatsu/Nissan/Mercury.