Craig:
We purchased a 6hp 4-stroke Tohatsu last year and LOVE it! It has been a great outboard. Moved our little Ariel from Cape Canaveral to Wilmington up the ICW without a hitch. Fits very nicely in the well. The long shaft doesn't cav even on a major heel.
BTW I have a used Suzuki 6hp 4-stroke for sale. PM for details but it's a great little motor too! New water pump and carby and fresh paint.. 2003 model I think?
Andrew
Somewhere on this site is a picture??
The boat yard owner just told me that the parts on my moter weren't broken but that the bracket holding them on melted due to the overheating problem. Just exactly what caused the overheating, I don't know.
Failure to regularly fresh water flush an ob can lead to salt build up in the ob's water pump and its water cooling channels. Been there, done that. Almost ended up on the beach! The old Johnson, however, stopped running before it started melting anything.Originally Posted by JBM
I just took a look at a Merc 6 (Of course same as the Nissan & Tomatsu) and noticed that the zinc is a TINY little square on the side of the lower unit. It look about 1" square.
Has anyone had a problem with them eroding really fast? It seems like it is about 1/4 the size of the one on the Yahama... seems like it would go really fast?
What have you seen?
On edit; Did find some discussion on OB motor zinc's here. Nothing addressing the little zinc on these motors though....
Last edited by c_amos; 06-05-2008 at 06:18 AM. Reason: To add link to prior zinc discussion.
Well, I just pulled the trigger on getting the little Tohatsu 6hp from onlineoutboards.com.
The price was right at $1265 with free shipping. They are out of stock on both of their lower pitched props.
I notice they have both a standard 6" pitch prop (~$65) and they also carry a new 5.99" 'High thrust' prop (~$100). The high thrust prop has large flat blades like the Yamaha high thrust prop does.
So now I have 2 questions for the users of the Merc / Nissan / Tohatsu 6hp.... I am still wondering about the zink, and would like to hear from anyone who may know if the new 'high thrust' prop is worth the extra $135?
Thanks,
Last edited by c_amos; 07-01-2008 at 07:47 PM.
Craig
Hubba-hubba. Is that the extra-long shaft? With the charging system? And the verticle pull??
Long, long ago Mike made a well grounded point that the prop pitch we wanted for our boats, running a small HP 4-stroke was a 7" pitch. Something about allowing the engine to run in the proper RPM range without getting a lot of slip.
Sorry I can't add anything useful to the zinc question. Would composition of the metal the zinc is attached to make a difference in the rate of oxidation/disolution?
As soon as the O'day sells online gets a hunk of money from me too!
Got the motor in the other day. Nicely packaged, looks to be pretty good gear.
Couple of interesting things I noticed. First, the fuel connector is not the same on the tank and the motor. The motor connector is the 'nissan' connector, kinda like the OMC, but not quite, nor does the Yamaha connector fit (although it is close). The tank connector looks exactly like the older (round) OMC type connectors... but I bet it is slightly different too. Not a big deal, especially since the motor comes with a new tank and line.
I opted for the 20" (really 22") shaft, not the 25"(27"). My Yamaha was 20" and never came out of the water. I see no reason to go 5" deeper, and pick up more drag, probably more crab pots, and not be able to stow it in the lazy-rat....
I did get the charging system. They charged me $145 for it. Again, had it on my last motor and it was nice to get a couple amps while motoring.
I went down to the boat today, was going to motor for a couple hours to make myself obey the break-in period (10 min at idle, 10min<1/2 throttle, 2hours <3/4 throttle, 3hours at 3/4 throttle.) Was a perfect day, with 10-12k and not too warm. Ran the motor a grand total of an hour....Had a nice sail though.
Motor smoked a bit, guess that is to be expected while the rings seat. There was a bit more vibration then the 2stroke had, but then it also was a 2 cyl.
I had a consistent 3kt, at less then 1/2 throttle. I have no doubt that it will push the boat to hull speed as others have reported.
I did just order the 'High Thrust' prop, it is a 5.9999" pitch, but it has the wide blades like the Yamaha 4 strokes do. I would have had the motor delivered with this prop, but no one offered swap outs. This is not the same prop as the 6" pitch prop, but a different animal all together (bet that .0001" pitch makes all the difference.
OBTW Tony, I found the reommendation Mike made on the 'outboard' thread;
Mercury ,Nissan & Tohatsu ( same motor, all made by Tohatsu ) recommend a 8x7 prop on the 6 ,5 & 4hp for displacement hulls ( the 4 comes with it ) the 6 & 5 come with a 'square prop' 8x8 ( actually 7.9x7.9 ).
My mechanic , from his experience , say to skip the 7 and drop to a 6 or 6.5 pitch . He's a licensed Nissan service center and seems to know what's up .
I'm going to buy a 8x7 try it and log with the GPS what it does then have it re-pitched to 8x6 and see what that does .
The following is over-simplified and not scientific;
at 4000 rpm the 8x8 prop is trying to go somewhere between 20 and 30 knots . Not going to happen on an Ariel .
At 4000 rpm the 8x6 prop is trying to go somewhere between 12 and 20 knots .
now you have slip and losses that can be 50% which brings you down to 6knots which is close to hull speed .
All that wasted revolutions on the 8x8 is like spinning the tires on a car , not getting you anywhere fast , the 8x6 is like switching to a fatter tire with more tread ,or a lower gear, that delivers all the bite to the road and propels you forward & stops you when you engage reverse.
The only drawback about downpitching ;
If you use the same motor on a dink or skiff that planes , it wont go as fast because you have shifted to a lower gear .
It only takes 5 minutes to switch props so buy a spare and have it pitched lower .
I also ordered a few spare zink's and a waterpump rebuild kit. I looked at the 'vertical pull' option, but at $129 I think I am fine just pulling at a bit of an angle. It is funny, I recall reading someone here say that the nissan vertical pull option routed the pull cord out the top of the cowl, the one offered now does not do that... it is just an elbow that screws to the recoil starter and comes out the front and turns up... seems like it would add a bunch of friction and chafe to me.. maybe they have some special stuff in there.For the price, maybe so.
Overall happy so far, will report the performance of the new prop when it arrives.
Last edited by c_amos; 07-01-2008 at 07:54 PM. Reason: To add a quote and make a long post even longer...
Yup, the first one eroded very quick a (about 2 months) and then the bolt broke off trying to change it, then I drilled through the plate with a bigger one that was sacrificial enough, so I ended up ruining the lower end. Tohatsu 6hp long shaft #1.
Above was in reference to the the question some time ago about the zinc. In a more general review of the Tohatsu/Nissan/Merc 6 HP I will say that they seem to have really small jets and I am having trouble keeping the motor running more than 4 weeks. I started the season with new gas after having had the engine serviced for trouble last season. I treated with Stabil Marine and within 4 weeks the carb was clogged with white mush. I cleaned it a few times and used Sea Foam. It started running again but 4 weeks later it was so clogged that I took it to a marina along with the line and the tank. They pronounced my gas fine, cleaned the carb and now 4 weeks later the carb bowl has white mush in it again and the motor wan't run. The marina talked me out of using aviation 100 low lead saying it would clog the rings but if I get that thing going I'm switching to ave gas and if that fails I'll sell that and move on. Which which other motors fit because I've had enough of this one? I didn't have much time to use it so basically this ruined the season. I've had guests waiting on board the last few times which we aborted when the motor wouldn't run. Basically we can't make a motor on its third season run more than occasionally. I'm going to take the carb off the old tohatsu with the ruined lower unit and try to make it to the marina to pull out for the season. AAAGH!
Last edited by Orca; 09-24-2017 at 02:40 PM.
Be sure to disconnect the fuel tank line from the engine at the end of the day and allow the engine to run until the bowl is emptied and the engines stops from fuel starvation. The owner's manual actually recommends this. The procedure accomplishes two things: it allows the engine some cool-down time to reduce thermal shock and -- more importantly, it empties the carb bowl so the fuel doesn't evaporate in the bowl every time you run the engine and eventually develop a residue.
100 "low lead" ("100LL") av gas should really be called: 100 lots of lead. It has more lead than leaded car gas once had. It will foul your plug. Yes, 10% ethanol gas will absorb water, but I doubt the water content is causing the fouling.
Last edited by pbryant; 09-27-2017 at 09:51 AM.
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