20HP Mercury Motor mount CLAMPS

[jhnglnnn]

I have a 20HP 1986-87 mercury tiller motor and the screw type clamps to mount to the transom have lost the round circular pieces. Can these screw clamps be replaced or What can be done to mount them? Thanks JOHN

 

[dazk14]

Re: 20HP Mercury Motor mount CLAMPS

The washer and screw can be purchased separately and are inexpensive. Will need the S/N to give you the specific part numbers.

 

[Yesterday]

Re: 20HP Mercury Motor mount CLAMPS

Mine just popped out today! It really doesn't look like there was much holding them in place. I know my 402 had ball tips pressed into a mushroom through the holes in the circular pieces, but my 850 doesn't even seem to have those. I used a vise to re-mushroom the tips on my 402's and they held up reasonably well. Most of the pressure holds them on, so as long as they're in place...

Around here O/B theft is high so I bolt my engines through the transom.

 

[jhnglnnn]

Re: 20HP Mercury Motor mount CLAMPS

I bought this engine for a low price because, unfortunately it had no serial number but I know it is either a 86, 87,88 or 89. According to the repair manual, the spark plug L76V is the one for the years listed above. However, the plugs that are in the motor are NGK's BUHW-2. If the spark plugs were L78V, then engine would be an 80-81. I am not sure how to compare spark plugs but that is the reason I believe it is probably the 86-89 year. I hope that helps. John

 

[dazk14]

Re: 20HP Mercury Motor mount CLAMPS

Post a pic of the motor and that will work. The parts for that vintage you are speaking are only about $7 total.

BTW- Those surface gap plugs were typically used in the 70's. Is the cowl square on the back or rounded?

If rounded - 70's, square 80's.

 

[Laddies]

Re: 20HP Mercury Motor mount CLAMPS

Without a serial number you will need to measure the diameter of the threads
:: iShopMarine.com ::

 

[jhnglnnn]

Re: 20HP Mercury Motor mount CLAMPS

Post a pic of the motor and that will work. The parts for that vintage you are speaking are only about $7 total.

BTW- Those surface gap plugs were typically used in the 70's. Is the cowl square on the back or rounded?

If rounded - 70's, square 80's.[/QUOTE]

Pics attached and cowl is square so much be 80's.

 

[dazk14]

Re: 20HP Mercury Motor mount CLAMPS

View attachment 181712View attachment 181713Post a pic of the motor and that will work. The parts for that vintage you are speaking are only about $7 total.

BTW- Those surface gap plugs were typically used in the 70's. Is the cowl square on the back or rounded?

If rounded - 70's, square 80's.

It's a 70's... and your getting warmer - a picture of the cowl/cover please. you'll need it for future parts anyway.

Pics attached and cowl is square so much be 80's.[/QUOTE]

 

[oldman570]

Re: 20HP Mercury Motor mount CLAMPS

Have you checked to see if the motor welch plug on the block for a SR# ? Should be round an about the size if a quaterwith numbers stamped on it.
Oldman570

 

[jhnglnnn]

Re: 20HP Mercury Motor mount CLAMPS

Have you checked to see if the motor welch plug on the block for a SR# ? Should be round an about the size if a quaterwith numbers stamped on it.
Oldman570

I will check it but not sure what a welch plug is. I will look in repair manual. ALso, I will post a pic of the cowl in case motor is a 70's. Thanks a bunch to y'all.

 

[oldman570]

Re: 20HP Mercury Motor mount CLAMPS

http://imageshack.us/a/img84/8224/391496208.jpg Depending on the tear of motor it will/should have a welch plug and the numbers stamped in it should be the serial number for the motor.
Oldman570

 

[jhnglnnn]

Re: 20HP Mercury Motor mount CLAMPS



here are cowling images

 

[jhnglnnn]

Re: 20HP Mercury Motor mount CLAMPS

with due diligence, i found the serial number and it is 4822872.

 

[jhnglnnn]

Re: 20HP Mercury Motor mount CLAMPS

s/n 4822872

 

[oldman570]

Re: 20HP Mercury Motor mount CLAMPS

My SR#book shows that the SR#4822872 is a 1977 motor. This along with the blue band is /or shoud be correct. I take it that you found the welch plug on the motor.
JMO, Oldman570

 

[dazk14]

Re: 20HP Mercury Motor mount CLAMPS

You have an early 1978. Please confirm if the open end of the clamp screw is threaded (or not). 77-78 was the change over year with the styles.

Edit - not to step on O'570...the numbers can be dizzying...beginning of run to end of run and this old man doesn't see like he used to.

 

[jhnglnnn]

Re: 20HP Mercury Motor mount CLAMPS

the clamp screws appear to be threaded according to the first pictures above unless I do not understand the question Chief. Thanks John

 

[dazk14]

Re: 20HP Mercury Motor mount CLAMPS

the clamp screws appear to be threaded according to the first pictures above unless I do not understand the question Chief. Thanks John

The threads I am referring to are on the end of the clamp screw that is missing the cup washer. Is the small stem internally threaded (they are small)?

 

[jhnglnnn]

Re: 20HP Mercury Motor mount CLAMPS

I understand. I will get this info and let you know as I am at work and will do so when I get home. Thanks again, John

 

[Laddies]

Re: 20HP Mercury Motor mount CLAMPS

No there are no internal threads on that type of clamp screw when cup went on and mercury dealers had a swagging tool or peined them with a hammer