9.8 Mercury Thnderbolt Ignition Motor I need HELP

[Mike Terry]

Hi all I am new to this forum. I need help. I am a Corvette guy but was given a 9.8 Mrecury Thunderbolt Ignition outboard boat motor from a friend. He said the motor runs but needs a new WATER PUMP where ever that is located and there are a few wires on the right side of the motor that need replaced. I know (NOTHING) about boat motors so I need your HELP. Where is and how do I get to, and replace the WATER PUMP? I need step by step info. Also I was told that there are 2 sizes of water pumps for the 9.8 hp motor, how do I know what size I need? Like I said I know NOTHING about Boat Motors so where is the Gas tank, I don't see it or is there an out side tank and if so where do I hook up the gas line to the motor? Is this an oil mix motor and if so what is the mixture I should use? Any information you could give me would be GREAT. I am going to put this motor on a 14ft flat bottom boat. If you can help me and or guide me thru this please e-mail me with your information on what I should do. Also, any idea what year motor this is. My e-mail address is mikes54vet@aol.com Thanks in advance for your helping me. Mike

 

[Barnacle_Bill]

Re: 9.8 Mercury Thnderbolt Ignition Motor I need HELP

Highly recommend you get a manual.

 

[7920hpMercury]

Re: 9.8 Mercury Thnderbolt Ignition Motor I need HELP

I have been a Mercury nut for a long time and now recently a Corvette nut too! Not too good being nuts about too many things though !

Anyway, 7.5, 9.8's and 20hp's are some of my favorite motors.

Need to know your year as determined from your serial number, see first or second post at top here. Your serial number will be on a plate in between your transom clamps or on the swivel bracket. Also Mercury sometimes puts the serial number on the block in different places. Once you know the serial number and year, get a service manual and maybe an owners manual off ebay. Good advice from the post above too. Mercury makes a service manual and Seloc service manuals are good too. You will also want a parts manual which you can order direct from Mercury.

Water pumps for 9.8's came in two different id's. The best route is the measure or mike where the water pump fits on the drive shaft. A service manual will show you how to locate and change.

Your gas tank is very likely separate. And you need to mix gas/oil 50 to 1.

One other item on Mercury's like this. Wires were aluminum, in the seventies anyway, and corrode worst than C3 frames! Sometimes you can splice with success.

For help, this forum is great and full of lots of helpful knowledgeable folks!