150 V6 Has no serial number, please help with year/model

daniel6762 · Jan 7, 2011

So there is no serial number on the transom bracket and no serial number on the core plugs.

I have recently stripped the engine due to #4 piston ring snapping and making a mess and are chasing parts to rebuild it but never realised that without a serial number it is near impossible. Hopefully someone here can help or get me close.

When I bought it I was told 1990 but now I believe it to be closer to early 80's model. Here's what I do know;

Its Black (but not a black max)
Block casting 8587788
Head casting 79741 (two piece)
Exhaust body/leg casting 1590-8334
Has vertical reeds
Pistons 765-7442
Con rods 644-818141
Carbs WH-33-1 / -2 / -3
Also on the block near the crank case flange is 022789 which someone told me is the date of manufacture (27 Fed 1989) but doesn't make sense because the heads are all one piece in the 1989 models ?

I will try post some pics soon.

Thanks

harry styles · Jan 7, 2011

Re: 150 V6 Has no serial number, please help with year/model

It looks like an early black max to me, Possibly around 88 but hard to say. The serial number will be stamped on the welch plugs. You can see them when you look down on the top of the motor.

Laddies · Jan 7, 2011

Re: 150 V6 Has no serial number, please help with year/model

Here's a good info source http://www.biggerhammer.net/mercury/

Faztbullet · Jan 7, 2011

Re: 150 V6 Has no serial number, please help with year/model

You got a mess, Its a 1989 3 piece cowling(2 lower ,1 upper), 1989 block (not the fat body block ) so it can use 2 piece heads from 1979 and up, it has 200hp heads and carbs, it is a 2.0 liter block, you have the top guided rods and should have the top guided pistons but the 7442 cast came both top & bottom guided. Sounds like somebody tried to increase HP with alot of misinformation..

Laddies · Jan 7, 2011

Re: 150 V6 Has no serial number, please help with year/model

Sounds like a FrankenMerc

daniel6762 · Jan 7, 2011

Re: 150 V6 Has no serial number, please help with year/model

Thanks for the great info, The block has already being bore 0.015 oversize so want to continue with the rebuild. Correct me if I'm wrong; I should be good if I order parts for a 1989 150HP like gasket/seal kit, pistons, bearings and head gaskets, water pump kit ? I'll have a look at the jets tomorrow to confirm if they came from a 200HP. I have added some more pics to the original post to help. 99% sure the pistons are top guided, can anyone confirm ?

Faztbullet · Jan 7, 2011

Re: 150 V6 Has no serial number, please help with year/model

Whoa!!!! !!!STOP!!! that block is a pre 83 as it has the old stlye heads that bolts to cylinder liner. You will need to order a gasket kit for a 79-83 V-6. You will need to order top guided pistons to work with the rods you have and top guided wrist pin bearings sets. Water pump same as 1989 model. Post a picture of the bottom of block so we can see if its a 150 or 175 block as the 150 has rectangular exhaust port and 175 has a ragged "D" shape!!!! If its a 175 you will need to see it it has matching exhaust plate and order different gasket set. You also need to check the main bearings as if it has the wrong style it will damage crank/bearings.This was a "cobbed" together motor,hope you didnt pay much for it..

daniel6762 · Jan 8, 2011

Re: 150 V6 Has no serial number, please help with year/model

http://s305.photobucket.com/albums/nn235/dbosanac/Mercury 150/

Dukedog · Jan 8, 2011

Re: 150 V6 Has no serial number, please help with year/model

Fb pretty much has it. Definitly first generation block, heads! 022789, builder picked up tha 8 instead of tha 7 stamp!................

daniel6762 · Jan 8, 2011

Re: 150 V6 Has no serial number, please help with year/model

There is a few more pics at the link above (if it works ?). Note the 3 piece cowls. So I'm looking at about an 82 model which is close to what I originally thought, except for pistons. Why would the previous owner use the 644-818141 con rods and pistons, are there advantages ? what are the benefits of running top guided pistons vs bottom guided or is it possible that these are original ? Anyway thanks for the input.

Faztbullet · Jan 8, 2011

Re: 150 V6 Has no serial number, please help with year/model

Note the 3 piece cowls

Someone cut about 3 inches off them to make them fit midsection. When any Mercury cowl is installed you will not see any of the mounting bolts.(except 4 some Hi-po versions) Thats what lead me to believe it was 1 piece upper cowl with lowers off. It also has the 3 ram trim which wasnt avaliable in 82.

Why would the previous owner use the 644-818141 con rods and pistons,

They came out of the original motor a late model motor they had.

what are the benefits of running top guided pistons vs bottom guided

Nothing on pistons, the top guided rods are said to be stronger than the 8181 series rods.

is it possible that these are original

Not for that year model block.....

daniel6762 · Jan 8, 2011

Re: 150 V6 Has no serial number, please help with year/model

Ha ! Would not of picked up on the cowls, walked outside and sure enough they've been trimmed up, you guys really know your Mercs ! Don't know why I hesitated for so long about posting a question on this forum, learn't more about this engine here in 2 days than in 2 month asking mechanics. Going to put it back together anyway with new pistons, use it for a while then probably get rid of it, then do some better research before buying my next. I'll probably be back with some more questions about tuning it later on. I'll let you know how I go. Thanks again and feel free to add more.

daniel6762 · Jan 10, 2011

Re: 150 V6 Has no serial number, please help with year/model

http://www.usboatsupply.com/Mercury_Mercruiser_Parts_Catalog3a.php?mc=01&ms=7150&si=299 This is from a 86 up block,

Where as this is from a 85 below block: http://www.usboatsupply.com/Mercury_Mercruiser_Parts_Catalog3a.php?mc=01&ms=7140&si=575

The poppet valve installation makes me think that my block may be 86 upward i.e. 89 model block ?? What are the other distinguishing features that make you convinced it is pre 83 ?

Aslo the block does have square exhaust ports in response to your earlier question Fastbullet.

Dukedog · Jan 10, 2011

Re: 150 V6 Has no serial number, please help with year/model

It is in fact a FIRST GENERATION pre '83 block. Head bolts attached ta tha clyinders are a dead give away...............Ya got a real life hoge-poge motor there. Front half has place for oil injecton shaft that your block nerver had. That would make it (front half) from an '84 ta '89 maybe. Vertical went away in '90 I think. Maybe later 135's still had vertial reeds. Don't remember for sure. Might be tha reason for tha later model rods n pistons?
Might have been a '94 up 135 ta start with and he destroyed tha block half and just replace with "something" that would work...............

Whatcha think Fb?

Dukedog · Jan 10, 2011

Re: 150 V6 Has no serial number, please help with year/model

Dukedog said:
Maybe later 135's still had vertial reeds. Don't remember for sure. Might be tha reason for tha later model rods n pistons?
Might have been a '94 up 135 ta start with and he destroyed tha block half and just replace with "something" that would work...............

Whatcha think Fb?

Musta had a brain fart! That can't be. Tha center mains won't work with that combination......

Faztbullet · Jan 10, 2011

Re: 150 V6 Has no serial number, please help with year/model

The main bearings should work as 2.0 from 91 and back are the same. I think your right Ddog that it was a 89-90 model motor and block took a s**t as that would explain the 818141 rods. Its a pre 83 due to mounting bolt pattern on heads and square exhaust will make it a 150.

Dukedog · Jan 10, 2011

Re: 150 V6 Has no serial number, please help with year/model

Tha reason I said "brain fart" is 'cause tha top guided rods didn't come out till '93/'94 which would have tha bigger center mains so tha two halves wouldn't match at tha center mains. Even though id is tha same tha od on tha fat block '91 is big and tha od of tha pre '91 is smaller. You with me now? Don't know if they had a vertical motor (135 maybe) then anyway. Justa 'nother piece ta add ta tha puzzle!

We havein' fun now?..............

daniel6762 · Jan 10, 2011

Re: 150 V6 Has no serial number, please help with year/model

We'll I've ordered a rebuild kit for 82 model and top guided pistons, hope this will sort me out, I'll be doing some serious comparing and measuring of new parts though before installation. Still doesn't explain the newer style poppet valve on my block. I thought this wasn't available till 86 ?

Does anyone have a pic of a 90's block out of curiosity ?

Dukedog · Jan 10, 2011

Re: 150 V6 Has no serial number, please help with year/model

daniel6762 said:
Still doesn't explain the newer style poppet valve on my block. I thought this wasn't available till 86 ?

Does anyone have a pic of a 90's block out of curiosity ?

Serial number 6042949 and below was tha dividing line between a type I and type II poppet assy. for tha first generation blocks. Just happens ta be tha later style also........

'91 and above look like a 2.5 block on tha outside, be it either 2.0, 2.4 or 2.5......

Faztbullet · Jan 10, 2011

Re: 150 V6 Has no serial number, please help with year/model

Just looked up the serial number for 91 135/150 and late 91 and early 92 could have had either rods. Merc has flipped floped on the poppet valve design several times over the years.Hey Ddog you still looking for a Bullet hull?
http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=816098+90

150 V6 Has no serial number, please help with year/model

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