intake/carbs

[quick007]

Hi y'all.im new to this site so...nice to meecha from freezing cold Maine.
My question is,on 77-79 merc 115 -90 hp.are carbs larger to make the added hp?
Is that the only change or are the intake ports larger too.both motors run a distributor.
1980 Gt-150 major reconstruct .
Thanx

 

[Chris1956]

Re: intake/carbs

Quick, It kinds depends on the year, however, you can check out the carb part numbers and get a clue as to whether they are the same. A lot of power differences were due to port timing and power boost pistons.

 

[quick007]

Re: intake/carbs

Quick, It kinds depends on the year, however, you can check out the carb part numbers and get a clue as to whether they are the same. A lot of power differences were due to port timing and power boost pistons.

Thanks for thereply Chris.im pretty sure only a couple of these had a distributor .
I think the 90 is a 1979 and the 115 is a 78.I've already swapped the distributor cause the 90 one went bad.

 

[Chris1956]

Re: intake/carbs

Distributors were phased out in mid-1980 on the IL6, I believe. Look at the transfer covers. The 115HP may have the boost port and ported piston.

Mid-70s models had other differences between the higher HP IL6 and the lower HP IL6.

 

[gwukena]

Re: intake/carbs

Distributors were phased out in mid-1980 on the IL6, I believe. Look at the transfer covers. The 115HP may have the boost port and ported piston.

Mid-70s models had other differences between the higher HP IL6 and the lower HP IL6.

1979 115 went to adi
1980 90 went to adi

Once hp got rated at prop shaft in early 80's the 115 basically became a 90 and the straight six 140 a 115

 

[Chris1956]

Re: intake/carbs

Of course the Merc IL6 150HP motor was renamed as 140HP when the 150HPV6 was introduced in 1978. It lasted a couple of years until renamed a 115HP IL6, although Merc may have detuned it some. The 150HPIL6 motors were pretty high strung....

 

[quick007]

Re: intake/carbs

Well sound like if i can figure out the easiest route i can have the 115hp on my Gt-150
even tho it will only be a 90hp again