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1982 440 fuel usage

P

prost

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"Greetings, My port motor on

"Greetings, My port motor on the last 3 occassions has burned approx 30 more gallons of fuel than the starboard motor. This is occurring over an average 6 to 7 hour run. ( I fill up after every trip.) It occured earlier in the spring after a fill up and the boat would not get on plane and I thought I determined it to be a plugged fuel filter. After replacing the filter the boat ran fine and after that fill up it they were within a gallon of each other. For the rest of the summer after every fill up I would experience the same symptons of the boat hitting a wall at 2500 RPMs. I would replace the fuel filter and all would seem well until I refueled and the port continued to take on approx 30 gallons more fuel.
I appear to be in sync according to my flash sync and the sound of the motors. My starboard motor does need to run a few hundred RPM's more than the port (according to the dash tachs). Where should I start? Sugggestions have been timing, distributor, stuck or collapsed valve etc. I'm the farthest thing from being a motorhead.... Oh by the way I have spent the last several days going thru this site and all I can say it is incredible the information that is here......
Randy"
 
"If it were any of the suggest

"If it were any of the suggested problems you listed, changing the filter would not have any impact at all! Sounds like you have a problem with that tank. I don't know what kind of fuel filter you have, but I'd change to a RACOR with a drainable (METAL!!!) water seperator, and check it after every trip. If you have a screw on cartridge type, RACOR has a two part replacement filter. The top section gets replaced "whenever", the bottom part is a drainable water seperator.I keep a coffee can on board to drain water seperator into. DO not drain into the bilge.

BTW... I'd check the vent line to the tank for that engine. Make sure its not flopping in the bilge. Locking gas caps might be a good investment, ... just in case you've annoyed someone... :)"
 
I have the old original brass

I have the old original brass canister type water fuel seperator. The vent line was mentioned before. When I intialy experienced the problem I went right to the water fuel seperator. when I went to drain the bowl it continued to drain as if there was some type of vacum which continued to draw the fuel.
 
"Randy:

Do you have, in add

"Randy:

Do you have, in addition to that water separator, a FINE fuel filter BEFORE the fuel pump? If so, move it to AFTER the pump.

One way to synch the engines extremely accurately is to make a SMALL turn, about 1 or 2 degrees, and listen to the motors. If the inside engine (of the turn) is running too fast, the synch will improve; it not, it will get words. Straighten out and bump its throttle up or down a tad (as needed) and you'll be perfect. Then try it in the other direction, just to be sure. Works slick!

Jeff"
 
"Randy:
The fuel should stop

"Randy:
The fuel should stop dripping. The law changed in 1979. There should be an anti-siphon fitting in the pickup of the fuel tank unless the elevation of the carb is higher than the tank pickup tube. Your separator may be mounted lower than the carb and tank pickup tube, causing the siphoning. If you don't have one, I would install one. They are cheap insurance."
 
Hey Jeff how goes it? I have a

Hey Jeff how goes it? I have a inline just before the carb as well as the thimble filter going into the carb
. Could the anti siphon valve cause the excessive fuel burn?
 
Probably not. How clean are y

Probably not. How clean are your flame arrestors? One of mine was dirty enough to cause a 20 % drop in gas mileage between the two motors.

Jeff
 
Well my mechanic was out last

Well my mechanic was out last night and the news is not good. 80 psi on the #2 cylinder and 100 on cylinders 5 and 7. Pulled the heads and a collapsed intake valve on both sides. Needless to say they are going in to be worked. Also the Carter on that motor was dialed out to 3 which he says the motor should run fine at 1 1/2 or 2. I don't think I have anti siphons so I will check after haul out and install them if not. Im going to have the others motors heads done as well for good measure. That one had 120 and 115 psi all around. I would think that after 26 years valve seals would be on order. Unfortunately I won't know until next spring I everything will be corrected since I won't be running anymore until then. The arresters are a little dirty. Geez why can't everything be simple...
 
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