77 Merc 1150 Carbs

[kevlar3000]

Wow what a cool site!!!! I have a 77 Merc 1150 that was recently rebuilt. Someone told me that the powerhead is the same as a 1400 and that just the carbs are different. Someone told me that the pistons are different too. So which is it? I would love to upgrade those carbs. What might something like that cost if it is even possible.

 

[ODDD1]

Re: 77 Merc 1150 Carbs

kevlar...you sure you got a 77? the zero on the end of your model number means it cant be newer than 75.... even so 115 thru 150 were same block...depending on year they had same internals,too. reed stop height and timing an max rpms determined power output. carbs changed too but bolting on a different set will gain you nothing! yur talkin about a 25 year old motor here......keep the rpms under 5500 an it might live a few more years......

 

[kevlar3000]

Re: 77 Merc 1150 Carbs

Hi,<br /><br />Thanks for the reply. It is definately a 77 Merc as the bad 1150 I traded in to get the rebuilt one was also a 77. I think it was was in 78 or 79 that they became just the 115. The guy who rebuilt the engine was an old merc racer from the early 60s and he did say that the 150 powerhead was different. That the 1150 was compatible with the 140 head as far as size goes. So it seems that there are a few different truths out there...<br /><br />. The only reason I would consider wanting to do this is that the engine has such a fresh rebuild on it.

 

[ODDD1]

Re: 77 Merc 1150 Carbs

Well, kevlar lord knows this wouldnt be the first time i was wrong about someting! i have built many inlines over the last 20years.....the last was a 1500. stock merc replacement pistons.....same ones yer 1150 takes....crank an rods are the same even replacement reed blocks have same stop height on them....porting may be higher in block...have never measured one. ican say that the stock 150's i have had on the dyno are generously rated a 150. optimum horsepower out of that block seems to be about 120hp....you can make that much without spinnin it to hard an breakin parts.....over the years timing specs have gotten conservative and main jetting has gooten richer all to try to deal with todays fuel...if you got stock jetting definately go up .002" just for safety.

 

[kevlar3000]

Re: 77 Merc 1150 Carbs

Hey I really appreciate the help. I was wondering if I could forward you an email that I got from oldmercs.com It was a guy at Grubbs marine that said the pistons were different. If I could get your take on what he said it would be great. If you don't want to leave your e-mail on this site I can leave you mine and you can send me your address there. I am kevlar3000@yahoo.com<br />Again your input is really appreciated because I keep hearing different things.<br /><br />Thanks<br /><br />Kevlar