[mrd5225]

I'm looking at purchasing a 1976 42' SF w/ 454 MarinePower engines. Anyone know what the fuel consumption is & approximate range?? Once the engines go I plan on repowering w/ diesels.

[jkp1]

Boy, I have to tell you, at 40,000 lbs loaded, the 42' Post never should have been set up with Gas. I own a 1980 42' Post with Detroit Diesel 6-71ti's pumped to 410 hp and it is just adequate.

Do not underestimate the hassle of converting from gas to diesel. You'll likely have to change out batteries, fuel tanks, lines, mounts, shafts & props in addition to the engines. Oh, don't forget your generator. Can't have diesel engines and a gas genny. You will save yourself alot of headaches by just buying a boat that already has diesels.

For performance with gas, figure 14-15 knots @ 3200 rmp burning about 35 gph. BUT the engines are highly loaded and will wear out every 1000 hours or so. Not sure of range, I hold 508 gallons but your tanks may be less.

By comparison, I cruise at 22 knots with 26 knots at top end. At cruise, I burn about 30 gph. The engines will likely outlive me.

[Gnautical]

I am new to Post yachts with the recent purchase of a 1997 47'.
I have lots to learn. For example I have yet to find the forward fuel compartment drain referred to in the manual. I also have taken off the swim plateform which is all fiberglass with a great boarding ladder mounted. It is up for sale.
I live in NJ not far from Post and have ready access to their services.

[alloyed2sea]

Originally Posted by jkp1

Boy, I have to tell you, at 40,000 lbs loaded, the 42' Post never should have been set up with Gas. I own a 1980 42' Post with Detroit Diesel 6-71ti's pumped to 410 hp and it is just adequate.

Do not underestimate the hassle of converting from gas to diesel. You'll likely have to change out batteries, fuel tanks, lines, mounts, shafts & props in addition to the engines. Oh, don't forget your generator. Can't have diesel engines and a gas genny. You will save yourself alot of headaches by just buying a boat that already has diesels.

For performance with gas, figure 14-15 knots @ 3200 rmp burning about 35 gph. BUT the engines are highly loaded and will wear out every 1000 hours or so. Not sure of range, I hold 508 gallons but your tanks may be less.

By comparison, I cruise at 22 knots with 26 knots at top end. At cruise, I burn about 30 gph. The engines will likely outlive me.

Yup, yup, what he said, only double now.
Gas motors are quieter/less smelly however.
Good luck!

[steven kennedy]

Originally Posted by mrd5225

I'm looking at purchasing a 1976 42' SF w/ 454 MarinePower engines. Anyone know what the fuel consumption is & approximate range?? Once the engines go I plan on repowering w/ diesels.

look too boat diesel . com a gent recently repowerd a 42 454 with yanmar , his before and afters are posted, ditto on the gas too desiel swap,,major stuff going on there,. i am presently undertaking the repower of my 42 , 1976 hull #48, she has/had 671 nats and lost my gear, twindisc 506, the new gear and rebuid was at about 30,000$ with out labor and would still be a heavy,plower at 18kn, so i've elected to go with a cummins zf package of 425each, and loose close to 2000# and project 24 cruse and 28kn wot @ 39500#turning 24/30 four blade

[Gin Ricky]

Originally Posted by Gnautical

I am new to Post yachts with the recent purchase of a 1997 47'.
I have lots to learn. For example I have yet to find the forward fuel compartment drain referred to in the manual. I also have taken off the swim plateform which is all fiberglass with a great boarding ladder mounted. It is up for sale.
I live in NJ not far from Post and have ready access to their services.

Hi Gnautical, is there any chance of getting a copy of your manual?