Help identifying a mercury black max

[Cowboy72]

My mid section serial number is 0g571198 but I think I have a different power head. The numbers I’ve found on the power head are right side where case meets 2731. Left side where case meets 945. Heads say 1026-5189 and also 380 with a circle around the number.carbs say1374-5427 and also wh3-1. Starter says 50-77141 also 09-25-78. There are no Welch plugs on top but there is one threaded plug on top in the center. Any help determining what I have is greatly appreciated.

 

[Chris1956]

1978 was the first year of the V6 Mercs. Is that what you have?

 

[Cowboy72]

Honestly I really don’t have a clue. I was hoping someone here could help me figure out what I have by the numbers I posted. I can’t afford to repower but I’m a good mechanic and wanting to do a rebuild on this engine. I just don’t know where to start when it comes to ordering parts.

 

[jimmbo]

The V6 was introduced in the summer of 1975 for the 76 model yr. It was initially a 175, then in 78, the 150, and the 200 were introduced

 

[Cowboy72]

Do any of the numbers mean anything to you in helping identify what I have?

 

[jimmbo]

Some of those Numbers are Casting Numbers, in a lot of cases they really don't help.

The WH-3 can identify the carb, and what it was supposed to go on.

Why do you think it is not the original Powerhead?

 

[Dukedog]

tha 3 "should be 150"... definitely not original power head with build date of '78.. first gen V6.. original motor was '97 150

 

[Cowboy72]

So Dukedog. You think the original build date is 78? I’m assuming you got that from the date on the starter. That would be a good start to finding out what this thing is. Are the starters year specific? I just wish I could find the original serial number. Compression is at 50 psi on all six cylinders. Seems odd to all wear out at the exact same rate. I have a suspicion that the starter is weak and therefore showing false compression readings. The starter gets hot and seems to turn the engine over slow . I will try to figure out how to post some pics today. That may help w I’d.

 

[GA_Boater]

Click on the Forum Help link in my sig and look at the photo attachment thread. You have 4 posts, so the new member Anti-Spammer restriction is removed.

The starter build date is a good dating tool only if the powerhead is original. The 50 PSI compression reading could be the tool, but being even is usually a good thing. Squirt some two stroke oil in each cylinder. the rings may be dry if the motor has been sitting.

Welcome to the forum, Cowboy.

 

[Dukedog]

wasn't payin' attention and didn't see that was tha date on tha starter but its probably right.. in tha picture below it shows where therewill be an actual "build date" stamped on tha block itself.. it may be really hard ta see but its there.. its on tha port side block half (back half of tha block assy.) on tha side kinda right behind that bend in tha timin' arm.. will be 1/8" numbers.. m/d/yr.

 

[jimmbo]

The Serial # 0g571198 checked out as a 1996 on two sites

 

[Faztbullet]

WH-3 carb only used in late 70's...as Duke suggested it sound like a old GEN1 block on a late model midsection...Franken motor

 

[Cowboy72]

Here are some pics thinking maybe 77 or 78 based on the info y’all have helped me with.

 

[Cowboy72]

[No message]

 

[Faztbullet]

1978/79 non finger ported 2.4 block 200Hp at powerhead...about 165 at prop or equal to a Xr4. Looks to have had a rough life as different head bolts on port side. Best to pull the heads and inspect cylinders as these model the chrome bore coating flakes off..This is a GEN1 block so order parts accordingly..hope you don't have a lot of $$$ in it,

 

[Cowboy72]

Thank you so much faztbullet. So if I understand you right it’s a 200 and not a 150? I don’t have much money into it at all. 300 bucks with the Skeeter boat and trailer. Lost my ranger 481 vs in a divorce. Man I miss that boat. So from here maybe rebuild depending on cost compared to repower. Thanks guys

 

[Faztbullet]

Not worth rebuilding a Gen1 block.....