EFI vs Carburated 9.9 Tohatsu

[hellosailor]

A friend of mine bought a Tohatsu 9.9 back around 1990, when no one in the US had heard of them. Day #1, he couldn't get it started. The problem was that the manual had the choke position (open/closed) backwards and once we got past that, it was flawless.

Last week he put it back on a boat after 14 years in the garage, so he called Tohatsu to ask about a manual and parts. They have manuals online for a 9.9b, 9.9c, and so on, and when he told the rep "No, just 9.9, it's about thirty years old" the rep was kinda boggled, but said all the important parts (like impeller) are going to be the same, just call and they'll check for him.

Good folks, good engines. EFI...just as in cars, it is great, until it goes wrong. If it is made well and doesn't have problems like a nearby lightning strike, it should go 25+ years without a hiccup. Can't get that out of any carb without repeated overhauls.

[Colin A]

Time well tell as it's a new model.
That said so far the most small EFI outboards seem to be doing really well. My family has a 25HP merc and that thing has been dead reliable for the last 6 years.
I haven't dealt with a dunked EFI motor (well not a small one) yet, but in general most modern outboards run an electronic ignition and I haven't seen many issues with those in short dunkings. I assume the electronics for the EFI would be potted, and the injectors sealed.

[Captain Bill]

I've had a suzuki 15 with efi for a little over three years. I will never own another carbureted outboard, especially a small one. The passages in these small engines are tiny and Ethanol gas does them no favors. The Suzuki starts easily and never misses a lick. I wouldn't worry about a lightning strike. Ever small engine made has a solid state ignition these days and if a lightning strike takes out the FI computer, the ignition system won't survive either and neither will the ignition on a carbureted engine, so you'll be rowing either way (assuming you're not crispy crittered). After years of fighting carburetors I suggest you take the EFI option.

[Avionics_Joe]

Any updates to this thread after more than a year?

I have an old 15 HP Mercury 2 stroke that I finally got running right, (the fifth time rebuilding the carburetor is the charm) and now the lower unit is leaking.

I am contemplating getting a 25HP Suzuki EFI to replace it, but I am getting sticker shock, the 20HP is a lot less but still pricey at $3,745.00.

I don't seem to be able to find the 25 without electric start and trim which I really don't want. Is it not available or am I just not finding it.

Maybe I should buy the tools to take the lower unit apart and rebuild it, or should I bite the bullet now and have a reliable motor as we are now living on the boat and will be using it a lot.

[Scaramanga F25]

I will never replace my old15 hp 2stoke Merc. It's only 74 lbs vs over 90 in a 4 stroke. Gas, bulb hose, and tank must be pristine. You would be amazed at the accumulated varnish (gunk) in the hose.

[a64pilot]

The 25 zuk is real heavy I think.
The 15 and 20 are the same weight as they are the same motor, just different levels of tuning.
I believe you can find one for about $3K if your in the US.
Only you can decide, or maybe buy a Yamaha Enduro if your island bound.
But so far I have had to do no maintenance on my zuk, except oil and filters every year.
I did sink the thing for 15 min or so and that took some cleaning and washing, several oil changes etc. but it seems to have survived.

[Avionics_Joe]

Originally Posted by Scaramanga F25

I will never replace my old15 hp 2stoke Merc. It's only 74 lbs vs over 90 in a 4 stroke. Gas, bulb hose, and tank must be pristine. You would be amazed at the accumulated varnish (gunk) in the hose.

Good point but as I have a catamaran I don't have to take the motor on and off so it is not as much of an issue. But still the 39.6 pounds more than the 20HP and 62.6 more than the old motor it is an issue I will have to consider.

[Avionics_Joe]

Originally Posted by a64pilot

The 25 zuk is real heavy I think.
The 15 and 20 are the same weight as they are the same motor, just different levels of tuning.
I believe you can find one for about $3K if your in the US.
Only you can decide, or maybe buy a Yamaha Enduro if your island bound.
But so far I have had to do no maintenance on my zuk, except oil and filters every year.
I did sink the thing for 15 min or so and that took some cleaning and washing, several oil changes etc. but it seems to have survived.

I saw your post about that dunking, I think it is a good reason to get the EFI if it can survive that.
Thanks for sharing that!

We cannot get the RIB on a plane with 3 people and gear with the 15 HP so I was thinking to go to the 25HP. Now if I can just get some quotes maybe I can make a decision.

[a64pilot]

Before you toss the 15 HP, make sure it’s propped correctly.
Get a cheap tachometer and check, if it’s overpropped it won’t plane.
I have a hard time with four strokes, after a lifetime of hearing two strokes, just about the time it sounds almost right, it hits the rev limiter, so I have to have a tach.
I can’t go by ear like I used to.
A waterproof inductive hourmeter / tachometer is about $12 on Amazon.
I’m getting one just for the hourmeter, tach is a bonus.