Tohatsu 20hp gear oil spec
I have recently acquired a Tohatsu MFS 20C and want to change the gear oil.
Having read around the forum that the Quicksilver brand is good, I bought some of their Premium Gear Lube SAE 80W-90, advertised as "for Tohatsu MFS20", from a retailer on Ebay. I specifed the outboard's model & serial when ordered to ensure no mistake.
Now, having received the oil I note on the product it states "Meets API GL-4", - but my tohatsu manual calls for API GL-5 spec.
So have I been supplied an unsuitable product for my needs? Even though the product description states "Meets or exceeds the needs of all marine engine manufacturers' gear lube".?
I don't particularly want to go back to the supplier and create a fuss, on the other hand I want confidence that I'm using the correct product so could anyone advise if this GL-4 spec gear oil is okay for my Tohatsu please?
My gut feeling is no, hence the question to someone who maybe has been down this road before.
Many thanks for advice folks!