1977 1500 inline six question about fuel

[OldMercsRule]

Hi folks, I can't stay away from craigslist this time of year, (darn it )!

I just bought a 1977 1500 with very good compression n' power trim, and I need to clean up a few matters and rearange some things from my parts engines prior to getting the old girl out on the lake and risking my life on a very light hull I aquired last week.

I run mid grade in my 1000s and my 1150s and also my 1250, (just picked it up too, darn it).

This girl is not a virgin as the rest of my old inline girls are cept the 'new' 1250, (it has two tell tale broken bolts that I am fixing), and may have the 1400 pistons in it, (as I did the last time I rebuilt a 1500), but there is no way for me to know that so I must assume it is the stock pop up pistons fer the 1500.

The compression is quite high and even across all six.

Do I run premium in this darn thing, or is that a waste of money?

Thanks in advance fer the sage advice. JR

 

[Chris1956]

Re: 1977 1500 inline six question about fuel

I always ran regular in my '77 Merc 1500. The consistant advise on this forum is to run mid-grade since today's gasoline stinks. I always found the fuel pump on that motor to be marginal. You might rebuild it first. Make sure the impeller is good, for obvious reasons. The power port pistons will be visible thru the transfer covers. 3 ring pistons were standard. The carb floats and inlet seats were superseded with better replacements than original.

Make sure all fuel lines and external filters are 3/8" in ID. Where are the broken bolts? On the head water jacket cover? If so, you shuld be able to drill thru the casting and install a nut on the backside. I used 1/4-20 bolts.

Congrats on the purchase.

 

[OldMercsRule]

Re: 1977 1500 inline six question about fuel

I always ran regular in my '77 Merc 1500. The consistant advise on this forum is to run mid-grade since today's gasoline stinks. I always found the fuel pump on that motor to be marginal. You might rebuild it first. Make sure the impeller is good, for obvious reasons. The power port pistons will be visible thru the transfer covers. 3 ring pistons were standard. The carb floats and inlet seats were superseded with better replacements than original.

Make sure all fuel lines and external filters are 3/8" in ID. Where are the broken bolts? On the head water jacket cover? If so, you shuld be able to drill thru the casting and install a nut on the backside. I used 1/4-20 bolts.

Congrats on the purchase.

Thanks Chris!

I hate to take the transfer cover off as it is a 'salty dog' from Florida, (I would surely break more bolts). The compression was within one lb on all six and the plugs looked very sweet.

I will hellacoil the two broken ones before I fire it, (did the compression check cold after two years no fire).

I can't find 100% dyno fuel in the Seattle area now. EVEN CHEVRON and 7-11 has 10% alchohol!! Grrrrrrrrrr. I will buy av gas and hope the dyno fuel returns so I don't have to go to Eastern Washington to get my fuel. Grrrrrrrrrrr.

I REALLY don't like the Soviet Union. Grrrrrrrrrrrrrrrrrrrr.

I will follow your advice on the fuel pump, (I had noticed that one is different from my 115s), when I was looking to make sure the mid, (see below), would be the EXACT same thing.

I have a pristine 1979 115 PT midsection that I bought from Idaho, (a freshwater one), that I will swap the power head to. HOPE I don't break more studs!!!!!!! I and I will swap the LU also fer a much MUCH nicer one where the prop is not stuck on it, (as the aluminum one is now).

I have a 19p stainless 3 blade wheel that I have been dying to hook onto an engine. Do you think the 1500 could swing that much wheel on a 1.78 to 1 LU that I have that is very sweet or should I stick with the 2 to 1 LU for that wheel? The guy I bought it from was overreving his 1986 115 inline with it that is why he sold it to me cheap.

The boat is a 1972 16 foot Bayliner ski type semi v that is very VERY LIGHT, and may make a better airplane then a boat. LOL.

It now has a non PT 1250 on it that I will get out on the ol' road first to see how much it scares me before the 1500 is hooked up to it. If the 1250 scares me I will not tempt death with the 1500!!

Thanks fer yer advice non alchohol mid grade it will be!!!! JR