Which motor is this (s/n confusion)?

[iam2sam]

I recently bought an 1973 Sea Nymph 16R72 deep-V equipped with a 2 cylinder 2-stroke Merc that is badged "40 HP Thunderbolt". The s/n on the motor tag is "OB272613". Those 8 characters are engraved or relief-stamped. There is space for a 9th character, but nothing appears in that space. According to the Mercury s/n lists I have found on-line, (OB)272613x would be a 1969 35 HP motor. I need to evaluate this motor to determine if I will keep or replace it on my boat. An accurate identification would seem to be a prerequisite for that evaluation, so I'm stumped at the beginning of this process. Can anyone here give me some advice or pointers on determining just what it is I have? Thanks.

 

[GA_Boater]

Welcome to iboats, Sam.

I come up with 1988 35HP, no idea why it has 40HP badging. SN B272613 falls in the range highlighted;



From here - http://www.maxrules.com/models/Merc_...30-40CYL2.html

If I misread, maybe someone else has an idea.

 

[Dukedog]

'88 35.. model number 1035312BD

 

[racerone]

Post a bunch of pictures of it.

 

[Dukedog]

serial numbers beginning with 0 and a letter will be followed by 6 digits...

go here for tha most accurate information....

https://webapps.brunswick.com/litera...atureSearch.do

"The s/n on the motor tag is "OB272613". Those 8 characters are engraved or relief-stamped."

if this "tag" in on tha clamp bracket then it may not be a match for tha actual power head... a lot of "outside parts" can be interchanged and/or made ta work in different combinations..

 

[iam2sam]

serial numbers beginning with 0 and a letter will be followed by 6 digits...

go here for tha most accurate information....

https://webapps.brunswick.com/litera...atureSearch.do

"The s/n on the motor tag is "OB272613". Those 8 characters are engraved or relief-stamped."

if this "tag" in on tha clamp bracket then it may not be a match for tha actual power head... a lot of "outside parts" can be interchanged and/or made ta work in different combinations..

It is on the clamp. I'll try to get some pics & post them on Monday.

 

[Dukedog]

maybe someone on here is familiar enough with tha "little" motors (mine being tha V6) ta know where ta look for a "block" serial number and/or a part on it that will distinguish a particular motor... gl.

 

[iam2sam]

No Title

Clues...

 

[Dukedog]

see post 2 and 3...... welsh plug matches clamp.

 

[iam2sam]

Clues...

It's nice to have 2 posters who know far more about these motors than I do agree on the ID. Unfortunately, this has added another element (beyond the 40 HP badging) to my personal confusion. According to the chart at the link in post #2, the "M" (manual?) indicates rope start. My motor has electric start. Is that a common conversion for these motors? Is it possible this motor was cobbled together from parts, and if so, are there issues I should watch out for beyond those typical for this motor series? Thanks again.

 

[racerone]

The stripes on the cowling indicate 81/ 82 / 83 model year.--So yes these parts may have been installed for cosmetic reasons.

 

[Dukedog]

Go to site in post 5 for anything ya need for it... lectric start was option... couda been added by dealer or any one else... tha first number is a "zero" before tha B... it was added in later years as numbers accumalated...

 

[GA_Boater]

The link Duke has in post # 5 shows it motor as ELO. Electric start, long shaft and oil injection. The first item in that link is for an Auto Blend system - Do you have an external oil tank, usually under the splash well, most definitely separate from the motor? It looks like this if a PO hasn't done the smart thing by dumping Auto Blend and gone pre-mix.