John,
As you mentioned, I can estimate how much fuel I will be taking on based upon engine hours, but the only way I can prevent the fuel from over-flowing is to listen to the fuel going in. When I get close to what I think will be full, I slow the pump down and listen. You can hear the change in pitch of the fuel coming up the filler hose. When you first start filling, there is hardly any noise. As the fuel reaches the filler hose, you can hear it, and as the fuel comes up the hose, the splashing sound becomes higher pitched. Not an exact science, but it's worked for me.

Always a tough one. There's no fuel at our marina so I refuel from jerry cans and I always pour it through a baja filter which has a very small outlet. So there really is no noise to hear, it actually will start coming out the overflow before I can detect a rising level in the filler hose. So I basically wait until we're close to 3/4s on the gauge, then I add a 20 litre can which I know it will easily hold. That the only system I have found that works in our unique circumstances.

Do a Google search on a [B]fuel whistle[/B] it goes in the vent line. I don't have one on my boat but it looks like a good idea, I would install it as close to the tank as possible so it drains back in to the tank

We installed a whistle - and it works well PROVIDING you are filling quickly (to make the whistle sound) and stop filling the instant the whistle changes to a gurgle.

I do what Tom suggests. I also stop the pump every once in a while to allow the foaming to settle down. As you know, John, our fuel gauge is "inoperative" and I use the engine hours as the sole source of fuel requirements. Been within 1/2 gallon for the last 13 years. I used to put an absorbent pad under the vent, but don't bother anymore. I bought one of those plastic jugs, but it didn't fit with our vent geometry at the transom. Good idea, but impractical I found out.

It's simply not worth trying to fill it to the teeny tiniest top like one could or would do with a car. 1/4 gallon less fuel at a fill up is a half hour motoring time for our engine, and I usually fill up when the tank gets half full anyway.

The fuel docks near us have nozzles so huge that it is a real effort to keep the tip of the nozzle in the fuel port and the rate regulated so as to avoid spillage.

My wife is pretty much always aboard for a fill, so she climbs over the rail with a rag under the vent and tells me when to stop. Once time I didn't stop the first time she told me to. I learned that it is a variable-volume alarm.

I used a 1 quart engine oil container - cut the top off and drilled a hole near the top about the size of the vent hole. I place this container on the vent hole and insert an absorbent towel in it. If the fuel starts to pour out it will end up in this plastic container. No spills and no clean up. I discard the towel if it spills into it.

[QUOTE=John Reimann;11319]Brilliant idea! but one question: Since I fill up from a jerry jug, is there any reason I couldn't just put the fuel back in the jug?[/QUOTE]

John, I think we are talking about a 'burp' of fuel no more than a shot glass worth. If you get more than that, you are really not paying attention. :)

 A Racor fuel/air seperator will take care of the problem, about $100 on Amazon or defender.
https://www.defender.com/product.jsp?id=133911
 

I purchased a vent line whistle for five bucks on sale at the local Marine store. I had to remove the rear panel in the AFT cabin and crawl up words to cut the line and install it, but it was easy to do once I was in there. As described above, it whistles when the fuel is going in and then gurgles when it tops out. Sadly, it doesn't work well if you are using a Jerry can.

It would be nice if there was a way to properly repair the gas gauges in our boats. I got disheartened after removing the float, readjusting it, and resealing it, only to have it continue to read three-quarters of a tank regardless of being empty or full.

I use a seacurefill system on my Mk1 it works well

les

I have a 1984 Catalina 36 Hul # 260 and the fuel gauge never worked.  It always read 3/4 full.  I purchased a new Sending Unit from Catalina Direct, just make sure you get the right one for your size tank ( mine was 33 gals. )  Now my gauge works great.  There is always the possiblity that the gauge is also bad.  The mechanic, if experinced can tall you which is bad.  I purchased both but needed only the sending unit.  The new design sending unit is so much better than the old design, it would be well worth replacing.

Captain Cliff