Mercury Thunderbolt 20 hp ...

[charles.wahlin]

I've bought an old Mercury Thunderbolt with 20 hp.<br />I don't know what year it is made, so I wonder if anyone know how I can get get that information.<br /><br />I also wonder if it really should be "grease" in the gear.<br />I can only find 1 hole to fill it up, and it looks like there is grease inside.<br /><br />On my previous outboard engines there has been 2 holes and it is is filled up with gear oil. Thats why I'm confused.<br /><br />/ Charles

 

[12Footer]

Re: Mercury Thunderbolt 20 hp ...

Post a model and seriual number, and someone here will be able to look in thier shop manual,and tell you which shop manual it's in.

 

[charles.wahlin]

Re: Mercury Thunderbolt 20 hp ...

Thanks a lot.<br /><br />I will get that information and send it to you. But won't be until next month, because the engine is located at our summer place.<br /><br />/ Charles

 

[12Footer]

Re: Mercury Thunderbolt 20 hp ...

No problem,Charles.I'll probably be here.<br />But if not, anyone with the book can give you the info.

 

[charles.wahlin]

Re: Mercury Thunderbolt 20 hp ...

I've got a serial number on my mercury 20 hp Thunderbolt for you now. It is 4055653.<br /><br />I hope you can help me find out if it is oil or grease inside.<br /><br />/Charles

 

[Doc Dave]

Re: Mercury Thunderbolt 20 hp ...

Charles,<br /> Your motor is a 1974 model.Lower gear oil changes same as any merc outboard,screw down low and one up high.<br />DAVE

 

[Sailor77.7]

Re: Mercury Thunderbolt 20 hp ...

Charles,

you can go to this website: http://www.oldmercs.com/
and you can find all sorts of information out about your engine. I found out what year mine was by going here.

Vr,

sailor77.7

 

[Laddies]

Re: Mercury Thunderbolt 20 hp ...

All 20HP mercurys since the Mark 20 use 90# gear oil