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tohatsu 6hp 4stroke question

L

lurchernz

New member
Greetings from Southern New Zealand. I have a merc 6hp four stroke (Same as Tohatsu).

I just changed the gearcase oil. When I went to the parts shop there was no outboard gear oil in stock. The guy said he used castrol EPX 80W/90 gear oil with no issues. Does this sound reasonable? Also I wanted to check the valve clearances I saw on here that 0.04 inlet 0.06 exhaust were the settings but how do I find TDC easily? I notice there is a hash mark on the flywheel, where does this line up? I have a maintenance and warranty manual but despite it having other useful service info about oil changes/gear oil changes etc it makes no mention of the tappets?
 
Yes, any good EP Hypoid 90 is fine for the LU. You just don't want the old Type C that was used for the OMC electric shift LU's way back when.

The Factory service manual, available from any dealer, probably even in NZ, has details on setting the valves. The timing mark lines up through a window with a mark on the block.
 
I rang the dealer he says 6 weeks to get a manual and the salmon are running here and I need my motor running sweet....

Can anyone tell me how to get to TDC? How about if I remove the spark plug and stick a length of dowl in there and turn the motor over till I feel it is at the top of the stroke will this work?
 
There are marks at the flywheel for TDC. If in doubt as to whether you are on compression vs exhaust stroke, put your finger over the plug hole, and you will know when you are on compression. Unless the motor has a lot of hours, or ran poor oil, the lash is likely OK. It's typical to develop a little extra clearance over time, which doesn't hurt anything, but will reduce top power output somewhat. Just don't run too tight, or you will burn a valve and/or seat.
 
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