Tohatsu 30hp 4 stroke fuel injection V.s Tohatsu 50hp TLDI

ForTuna · February 03, 2014, 21:15:20 CET

Good evening to you all.

As Baghira was saying before these last couple of years unfortunately I was not able to use the boat as much as I wanted too due to work/study commitments, however In the beginning it was rather the opposite. I used to fetch fishing grounds of not less than 20 miles out during Lampuki season so I used to get very close to 100hrs per season or more.

Today's engines ( all brands ) are pretty much reliable, being two stroke or four stroke. I personally have opted to go for Evinrude as at that time it was the lightest 75HP on the market. Nothing against the Brand , today I may consider also the new Yamaha F70 due to its light weight.

I think you really have to shop around carefully nowadays, decide on the HP desired, then consider if you want a smooth engine and you can afford those extra kilos and go for a 4 stroke or lighter engines and go for a 2 stroke.

I am strongly considering to upgrade to a 23 ft with a maximum rating of 175HP and at the moment I am still Pro Etec being almost 20kg lighter than its closest 150HP 4 stroke rival and you have the benefit of extra 25HP under the Cowling which will be of great help to plane faster....(again same engine as 150HP but tuned more) it all goes down to a personal choice more quite engines or faster and more torque....

As for your question about Yamaha Malvizzu if I am not wrong :

the F70 has the same engine block of the 50HP but it is tuned more. You get more HP out of a small engine (1000cc)

While the 75 has a bigger block probably around 1300-1400cc of course than it gets heavier.

The_Gaffer · February 03, 2014, 23:07:04 CET

Correct! Also, the F70 is a SOHC engine while the 75HP are DOHC. Most of the reviews on this new revolutionary outboard state that the revs attained by yamaha F70 have been tested in moto GPs where Yamaha lead the way driven by a certain Valentino Rossi. Better known as a revhead!. So a lot of R&D has gone into this outboard before it was launched. As for being a tuned up engine, yes it is, but revolutionary, as the low rev and mid range grunt is equally impressive. Again, yamaha techies attribute this to the impressive motorcycle range, where acceleration, speed, longevity and reliability are impressive. Im pasting a link to a review on this new Yamaha F70.
http://www.fishingworld.com.au/news/fuel-miser-tested-yamaha-f70-four-stroke

By the way, did I mention the fuel burn on this outboard?, boats similar in weight and hull to the petecraft 16' will run at 22knts burning 10ltrs an hour with medium load and 2 persons on board.

kris · February 04, 2014, 09:49:25 CET

@The_Gaffer impressive fuel consumption Joe! When you did your shopping around for different outboard brands, did you get any concrete fuel consumption charts? Or you had to search yourself on the internet? And regarding the purchase, I guess you got your Yamaha from Gasan Group right?

Unfortunately, the only brand to willingly provide its fuel consumption charts are Tohatsu. Now of course these may be biased, for the simple reason that they are supplied by the manufacturing company itself. When I try to find any fuel consumption info on other brands it is simply non-existent if it weren't provided by certain guys who do test runs $:-\$

malvizzu · February 04, 2014, 09:51:15 CET

Great feedback guys. Thanks to all.

malvizzu · February 04, 2014, 18:38:34 CET

I have been doing some research on the net. The Yamaha 6HP states to be a 2-cylinder @ 28kg while the Tohatsu 6HP states to be 1-cylinder at 26kg. What's the advantage of the extra cylinder?

lazyfisherman · February 04, 2014, 20:42:19 CET

Twin cylinder engines should be smoother and quieter with less vibration.

ganni · February 05, 2014, 00:07:58 CET

Much much smoother since they are more balanced

baghira · February 05, 2014, 08:38:41 CET

From personal experiance.
I own a 1 cylinder motorbike...and I also had 2 cylinder bikes..
Both were reliable.
1 cylinder = (I still own the bike and the engine is a yamaha 660cc) Very reliable, vibrates, noisy, limited top speed, less consumption (I think), but it can tow whatever (impressive torque), Very difficult to leave it on low revs. / speed since that there is 1 piston going up and down and it is th only combustion that will make the engine rotate.
2 cylinder = more balanced output, less vibration, less noise, more revs, more top speed, is capable of going at low, more consumption, less torque.

malvizzu · February 05, 2014, 10:29:16 CET

Nice description Baghira. Thanks. So what are your suggestions for a 6HP auxiliary to be used mainly as a back up? I don't know the price of Yamaha yet, only that of Tohatsu, Evinrude and Suzuki. By the way, could not find the Yamaha 6HP 2-cylinder again, probably confused with the 8HP when searching.

Tohatsu = €1250 (incl tank), 1-cylinder, displacement 123cc, weight 26.6kg
Evinrude = €1350 (incl tank), 1-cylinder, displacement 123cc, weight 26.1kg
Suzuki = €1600 (w/o tank), 1-cylinder, displacement 138cc, weight 25.9kg
Yamaha =

; 1-cylinder, displacement 139cc, weight 28kg

kris · February 05, 2014, 10:45:14 CET

Ok guys found quite a few reviews regarding 1 or 2 cylinder engines. However, does it really make a difference between a 3 and 4 cylinder when used as the main engine? (in my case I am talking about a 50hp of course)

@Malvizzu...I have an auxiliary 2-stroke 3.5hp long shaft nissan as a backup. It only weighs 12kg if I am not mistaken. I have chosen the lightest possible engine because of the weight to carry around in my car and onto the boat, to mount and unmount for use etc. A 4-stroke is much heavier and one cannot store it in a compartment because of the engine oil, unlike the 2-stroke which can be put facing up.

So if I were you I would opt for the lightest possible, my opinion anyway

Granitu · February 05, 2014, 11:11:15 CET

Quote from: malvizzu on February 05, 2014, 10:29:16 CET
Nice description Baghira. Thanks. So what are your suggestions for a 6HP auxiliary to be used mainly as a back up? I don't know the price of Yamaha yet, only that of Tohatsu, Evinrude and Suzuki. By the way, could not find the Yamaha 6HP 2-cylinder again, probably confused with the 8HP when searching.

Tohatsu = 1250 (incl tank), 1-cylinder, displacement 123cc, weight 26.6kg
Evinrude = 1350 (incl tank), 1-cylinder, displacement 123cc, weight 26.1kg
Suzuki = 1600 (w/o tank), 1-cylinder, displacement 138cc, weight 25.9kg
Yamaha = ; 1-cylinder, displacement 139cc, weight 28kg

Malvizz... go for a 9.9 and modify its prop (eg make it a 2 blade prop or a small prop so that it goes down)

These small outboards tend to suffer from clogging in the cooling over time since the cooling canals are relatively small...

malvizzu · February 05, 2014, 12:06:17 CET

@Granitu - as much as I would prefer a 9.9HP I cannot because my boat is only a 14 footer and it would be way too heavy as an auxiliary. Even Petecraft advised me to go for a maximum 6HP. Even with a 6HP I already have a problem fitting on the boat. I already have an auxiliary bracket but when I tried a Honda 5HP the steering rod of the main engine collides with the auxiliary keys when turned to one side. So I have to make different adjustments.

@Kris - I believe that a 2-stroke engine has more torque than a 4-stroke, so the equivalent of a 3.5HP 2-stroke is a 5HP or 6HP 4-stroke. I stand to be corrected. I was considering buying a 2nd hand good 2-stroke engine to have less weight but than I have to have two separate fuel tanks, one with clean fuel and another with fuel+oil for the 2-stroke. And that's a bit of an inconvenience.

kris · February 05, 2014, 12:16:24 CET

@malvizzu true enough, my boat is a 15ft 310kg hull + 71.5kg outboard...making it around 400kg in all. With the 3.5hp 2 stroke and 3 persons on board I managed to reach 4.5knots at full throttle, which I think is quite good. What I do regarding the problem of the oil is I just keep a small jerry can of 2-stroke oil on board and never mix it with fuel unnecessarily. My 2 cents is this...as an auxiliary I do not need speed...I just need a reliable small outboard which is capable of firing up without any problems and to bring me safely back to port...even if this may take an extra 30min when compared to a 5hp or 6hp

malvizzu · February 05, 2014, 12:28:55 CET

More or less I have the same weight as yours Kris, boat 300kg and engine 110kg. I thought of doing what you proposed as well regarding carrying oil separately.

baghira · February 05, 2014, 13:07:36 CET

These small outboards sometimes are inclusive of fuel tanks, and all you need is a small amount of fuel + oil.
Make sure to empty the carburetor every time after starting it a bit every now and then, 2 stroke forms a gelatinous substance when not in use, and left still mixed up with fuel. I have no problems to start my chain saw every season after 7 months on the shelf.
I would def. not go for a 9.9 for your boat. Too large and heavy to carry. If its use is going to be just as a backup in case of an emergency, I would go for ths smallest 2 stroke engine that can displace your boat with 3 persons on board. Amongst the brands you mentioned, i would go for the cheapest, and lighter. But aslo i would opt for a second hand.

If I was to buy one, i would choose it differently since that I would need it a bit larger, and I would never remove it, and would also use it for trolling.