fuel reqirements merc 115

[ponyboy]

this is my first 6cyl merc. I have been reading the board and it seems I should be running good fuel in my engine. its a 74 115. as I remember in the 60s the Fast merc's allways ran White gas? I have been using pensoil tcw3 and whatever gas is cheep.

[gaineso]

If you'll read the thread "Please HHEELLPP", I think you'll find all the reasons you need to use GOOD, as in premium, gas.

[Raceman]

Here's the link:

http://forums.screamandfly.com/forums/showthread.php?s=&threadid=31559


Great looking boat by the way. Post more pictures.

[Raceman]

If the stickers and front plate on that engine are original it is a 72, 73 or 74 and has high domed pistons if they haven't been changed, and it has higher gas requirements than the one in Gainesco's thread. Incidentally, fresh gas is as important as good gas. Oil companies now admit that in 6 mos the characteristics are changing.

Premium unleaded, full synthetic at no leaner than 40:1, timing no higher than 21º, propeller for proper RPM at full throttle, annual, or no more than bi-annual waterpump and gear oil changes and the engines are very reliable.

[ponyboy]

I did read that thread and on 2 ocations I had a light miss running speedway medium grade fuel,I replaced the plugs and it did it again but i don't see any aluminum on the plugs!!TG. Should I run the syn. oil? I bought this engine used and have no hist on it I does push the yellow monster to 50 + mph,Should I use last years fuel in my old 18 evinrude instead of topping it off with fresh?
Other questions I have are what spark plugs should I use,gear lube etc. I also have a light leak in the starboard trim cyl at the ram.is it an easy fix?
and after I run this engine hard for an hr the reeds get loud at lower spds. Is this my ears or normal? I also have a chance to buy a blue stripe 140 cheep, any info good or bad on this motor would help me make up my mind,will my harness from the 115 fit the 140? thanks for listening.:confused:

[ponyboy]

OH and how do ya get your pic on the left under your name??:D

[Raceman]

With today's fuel, I wouldn't run old gas in anything I care about. Based on several people's experience, the Pennzoil FULL SYNTHETIC is about as good as anything available. Be careful and get the FULL SYNTHETIC and not the blend. Walmart sells both. The harness of your engine will fit the blue striped 1400, which was made in 72 only. There's nothing bad to say about the 1400. It's exactly the same engine as the next year's 1500 with the exception of the power port in the side of the pistons and the corresponding trench in the cyl wall. Your blue 1150 doesn't have it either, although the later 1150's did. I've always used the Merc green High Perf. gear oil in my gearcases. Somebody else will have to answer the trim cyl rebuild question, I've never been in one.

One more thing that's extremely important on these engines. Too much RPM at full throttle is better than not enough. If you lug it with too much pitch it's more likely to burn pistons also. Although the 1150's don't like to turn like the 1500's, something at least in the mid 5's is much better than the upper 4's to low 5's that I think the old recommended operating range was listed at.