1971 thompson 4 cyl

isimar

Petty Officer 3rd Class
Joined
May 12, 2012
Messages
81
had a old friend gave me his boat today, it's been sitting for 6 years so i'm expecting to spend some money. a few questions 1. the manual says to NOT use unleaded fuel(my friend said he always put regular unleaded in it)..can't anyone shed some light on this ?
2. he said the motor ran fine when put away 6 years ago, so i'm thinking i'll have to pull the tank and lines from varnished fuel...anyone got other suggestions ?
3. it's a 2 battery setup, do i use one starting battery and one deep cycle or just two deep cycle batteries ?
4. what's the best way to clean the grime and mold off the cover and interior ?

any other input on what i have to prepare for on this old girl would be appreciated..

thanks in advance.
 

Bondo

Moderator
Staff member
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Apr 17, 2002
Messages
71,082
Re: 1971 thompson 4 cyl

Ayuh,... Welcome Aboard,.... What 4 cylinder motor,..?? Who's drive,..??

Boat motors rarely run enough hours in their lives to worry 'bout leaded gasoline...
If the valves recede into the head, a valve job, 'n new seats is the fix....

Ya, I'd drain the fuel system clean it, 'n start fresh... Ditto the motor's fuel system...

I'd just put 1 battery in it for now,... just to see if it runs...
 

isimar

Petty Officer 3rd Class
Joined
May 12, 2012
Messages
81
Re: 1971 thompson 4 cyl

Ayuh,... What 4 cylinder motor,..?? Who's drive,..??

Boat motors rarely run enough hours in their lives to worry 'bout leaded gasoline...
If the valves recede into the head, a valve job, 'n new seats is the fix....

Ya, I'd drain the fuel system clean it, 'n start fresh... Ditto the motor's fuel system...

I'd just put 1 battery in it for now,... just to see if it runs...

it has the mercruiser stern drive.
thanks.
 

Bondo

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Staff member
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Apr 17, 2002
Messages
71,082
Re: 1971 thompson 4 cyl

it has the mercruiser stern drive.
thanks.

Ayuh,.... That's an Oldie, that's gonna bring challenges,...

Head down to the Mercruiser forum, 'n take a peek into the Adults Only section, pinned to the top of the forum,...

Lotsa Great info up there, 'n the shop manuals to boot...
 

isimar

Petty Officer 3rd Class
Joined
May 12, 2012
Messages
81
Re: 1971 thompson 4 cyl

Ayuh,.... That's an Oldie, that's gonna bring challenges,...

Head down to the Mercruiser forum, 'n take a peek into the Adults Only section, pinned to the top of the forum,...

Lotsa Great info up there, 'n the shop manuals to boot...

challenges ??? oh dear lord what have i gotten into !
i thought the mercruiser forum was where i posted this to start with...
maybe i'm getting to senile to tackle a boat when i can't remember where i post things....lol
thanks..heading to the other thread.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: 1971 thompson 4 cyl

Keep in mind, we have many kinds of forums for different subjects. http://forums.iboats.com/forum.php
Fuel tanks an cleaning here in the Boat topics forum
Engine and drive problems belong in the Mercruiser forum
Electrical system (battery setup questions) in the Electrical forum.
If you want to fix scratches, or paint the boat, look in the Restoration forum.
 

isimar

Petty Officer 3rd Class
Joined
May 12, 2012
Messages
81
Re: 1971 thompson 4 cyl

Keep in mind, we have many kinds of forums for different subjects. http://forums.iboats.com/forum.php
Fuel tanks an cleaning here in the Boat topics forum
Engine and drive problems belong in the Mercruiser forum
Electrical system (battery setup questions) in the Electrical forum.
If you want to fix scratches, or paint the boat, look in the Restoration forum.
thank you sir....if i don't have a stroke trying to figure what everything is on this boat.
it seems in good repair, just lots of barn dust on the cover and the motor is really clean. the man kept every receipt for all the work he's had done to it over the years, so once i learn what certain things are...i'll be fine.
thanks for your help.
 

NYBo

Admiral
Joined
Oct 23, 2008
Messages
7,107
Re: 1971 thompson 4 cyl

Welcome to iboats!:cool:

Modern unleaded contains ethanol in many (most?) parts of the country which probably won't play nicely with 40+ year-old fuel system parts, especially if the fuel tank is fiberglass. Not sure why '71-vintage unleaded wasn't recommended. The main purveyor around here back then was Amoco, and the unleaded was high octane.
 

isimar

Petty Officer 3rd Class
Joined
May 12, 2012
Messages
81
Re: 1971 thompson 4 cyl

Welcome to iboats!:cool:

Modern unleaded contains ethanol in many (most?) parts of the country which probably won't play nicely with 40+ year-old fuel system parts, especially if the fuel tank is fiberglass. Not sure why '71-vintage unleaded wasn't recommended. The main purveyor around here back then was Amoco, and the unleaded was high octane.

i called the previous owner and asked him about the leaded/unleaded issue, he said he always filled it with the 87 octane unleaded and everything was fine.....
 

NYBo

Admiral
Joined
Oct 23, 2008
Messages
7,107
Re: 1971 thompson 4 cyl

It's very possible that the fuel system (lines, carburetor gaskets, etc.) were updated over ther years.
 

isimar

Petty Officer 3rd Class
Joined
May 12, 2012
Messages
81
Re: 1971 thompson 4 cyl

It's very possible that the fuel system (lines, carburetor gaskets, etc.) were updated over ther years.

there's probably no way to find out either..i see the lines are copper, can't see the tank.
 
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