doug748
Well-Known Member
Is it SAE 80 for the gearbox of my Tohatsu 3.5hp? Can I use the inexpensive stuff from the car shop or does it have to be a tube of the finest from the chandlers?
Tohatsu gearbox oil
- Thread starter doug748
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VicS
Well-Known Member
Outboard gear boxes usually use an 80W90 or 75W90 gear oil to API GL5 spec with added corrosion inhibitors to guard against the effects of water ingress. (There are exceptions such as old OMC outboards with a hydraulically assisted electric gear shift)
Tohatsu do not seem to offer the owners manuals online, at least I did not find them, so have not been able to check the recommendation.
I am also told that automotive oils foam too much ... but I did not say I belived that.
I use ordinary EP90!
BTW you know the normal method is to fill from the bottom until the oil flows from the top plug. Also a good idea to replace the washers or O rings on the level and drain plugs as these are a frequent source of water ingress I am told.
Tohatsu do not seem to offer the owners manuals online, at least I did not find them, so have not been able to check the recommendation.
I am also told that automotive oils foam too much ... but I did not say I belived that.
I use ordinary EP90!
BTW you know the normal method is to fill from the bottom until the oil flows from the top plug. Also a good idea to replace the washers or O rings on the level and drain plugs as these are a frequent source of water ingress I am told.
Heckler
Well-Known Member
thread drift a bit, on my md22 engined gearbox it says synthetic 75/90 gl5, i spotted some gear oil in my local auto shop, semi synthetic 75/90 gl5, i think from that we can safely deduce that it will work ok in marine boxes??
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doug748
Well-Known Member
Thanks Vic. After further research I find the specified oil seems to be:
" Genuine gear oil " or " API GL5 SAE #80 "
I wonder if anyone has found this cheaply available down the car shop? If not I am tempted to join you with the EP90.
" Genuine gear oil " or " API GL5 SAE #80 "
I wonder if anyone has found this cheaply available down the car shop? If not I am tempted to join you with the EP90.
Kyle2
Well-Known Member
The Owner's Manual states "Genuine Gear Oil or API GL5, SAE #80 to #90". I used a tube of outboard gear oil from a chandler's. Perhaps there are cheaper alternatives?
VicS
Well-Known Member
It is almost worth buying a tube of outboard gear oil then you have the tube for future use even if you decide to buy cheaper oil.
jim99
Well-Known Member
Attracted to this thread because I have a Tohatsu 3.5 on order...
Wonder if it would be safer to switch back and forth from the outboard gear oil to the car oil... at least until I am over the thrill of having a new thing.
Wonder if it would be safer to switch back and forth from the outboard gear oil to the car oil... at least until I am over the thrill of having a new thing.
charles_reed
Well-Known Member
3.5 is a superb engine (either in mercury or mariner guise). The best power/weight ration of any small OB.
Weaknesses are the gearchange on the powerhead, which tends to seize, and the fuel tap which tends to disintegrate.
I'm on my 3rd (1st two got stolen). Only problem in the EU they're banned as being to noxious for the environment.
You can quite happily use EP 80 gear oil, just change it regularly. Getting it in can be a problem, you need a lot of pressure to force it in - I cheat by putting it on its aide at a slight upward angle so the air van get out.
Weaknesses are the gearchange on the powerhead, which tends to seize, and the fuel tap which tends to disintegrate.
I'm on my 3rd (1st two got stolen). Only problem in the EU they're banned as being to noxious for the environment.
You can quite happily use EP 80 gear oil, just change it regularly. Getting it in can be a problem, you need a lot of pressure to force it in - I cheat by putting it on its aide at a slight upward angle so the air van get out.
VicS
Well-Known Member
[ QUOTE ]
happily use EP 80 gear oil, .......... Getting it in can be a problem, you need a lot of pressure to force it in - I cheat by putting it on its aide at a slight upward angle so the air van get out.
[/ QUOTE ]
Straight EP 80 and EP90 oil seems to have largely been replaced by 75W90 and 80W90.
If it is warmed slightly it is a lot easier to get in.
You should be filling via the drain/filler hole ... the bottom one, with the motor upright until oil flows from the top one.
happily use EP 80 gear oil, .......... Getting it in can be a problem, you need a lot of pressure to force it in - I cheat by putting it on its aide at a slight upward angle so the air van get out.
[/ QUOTE ]
Straight EP 80 and EP90 oil seems to have largely been replaced by 75W90 and 80W90.
If it is warmed slightly it is a lot easier to get in.
You should be filling via the drain/filler hole ... the bottom one, with the motor upright until oil flows from the top one.
charles_reed
Well-Known Member
Not in Italy they haven't.
Yes, I do fill through the lower hole - at 28C warming is probably unnecessary.
Yes, I do fill through the lower hole - at 28C warming is probably unnecessary.