Gas Cap/tank Question....

MASTERBrian

Petty Officer 3rd Class
Joined
Apr 16, 2011
Messages
84
I have a 1990 Bass Buggy Pontoon, the gas cap is one that has the fuel level gauge built in and was made by Kelch Corp. The problem is the lens was so dirty, it was unreadable, but now the lense broke and so now it seems the tank is unable to hold pressure. I've been searching online for boating stores that carry these, but I am unable to find them. I did search ebay and seem to have found some by this manufacturer, but they appear to be for snowmobiles and such.

Any idea if they should all be interchangeable if I get the right length of sensor? I measured the outside of the threads and it's about 2-1/4", is that the measurement I take?

What about venting? Do these tanks vent or not? I just picked this boat up and there was a screw in a hole in the top of the cap....


The other question I have regarding this is, is there any way to add an electric sensor to the tank so I can put a gauge in the dash?
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Texasmark

Supreme Mariner
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Dec 20, 2005
Messages
14,569
Re: Gas Cap/tank Question....

Electric sensors use an alum plate of about 3" in diameter and a cork gasket. Hole is drilled in the top flat portion of the tank with room for the float to move up and down with the level of gas. A ground wire to batt- goes to one of the plate mounting screws. The insulated terminal goes to the - side of the gauge. If you have a Merc engine, switched 12v is the purple wire under the dash and that is your hot lead to the sender. Most after markets have an adjustable float arm to fit varying tank depths. Best to set the float so that when the gauge says empty, you still have some fuel...you determine how much you need, to get you back to port.

A company by the name of Temple or Tempest or something like that make a lot of marine accessories as does a company named Mueller. I know Mueller makes the tanks and maybe sell after market gauges and sending units. If you are going to cut a hole in your tank and mount one, get info on safely messing with tanks....full of water, carbon moxide from your engine exhaust for a couple.

Mark
 

guy48065

Chief Petty Officer
Joined
Aug 31, 2008
Messages
427
Re: Gas Cap/tank Question....

Your old cap & gauge looks identical to most generic caps of that type found on generators, riding mowers, etc and sold on eBay for cheap. I'd sure take a chance on a cheap replacement rather than pay exorbitant OEM replacement cost. If it doesn't work you're only out $14. If you go the sensor route then buy a "universal" replacement cap with no gauge from Tractor Supply, Home Depot, etc. I'm pretty sure they're all the same size & pitch as long as it's not a more recent metric-from-China cap found on import equipment.
 
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MASTERBrian

Petty Officer 3rd Class
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Apr 16, 2011
Messages
84
Re: Gas Cap/tank Question....

Guy, I'll look at some of my lawn equipment, but I don't think this is the same, luckily I did find some specs on it, now I just have to find the right replacement cap. What I don't know is do I need a vented cap or not? For now I gorilla glued the lense back together.... I agree on the $14 range, that's what I've been eyeing, the dealer wants $80!! What gives????!!!

Looking at the electric sensors, they just screw directly into the tank....will this work for all plastic tanks or are they all made from different materials? Again, this is off a 1990 Bass Buggy. I figure if I go this route, I'll fill the tank with water then drill the hole! Probably after several rinses with soap and water!
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,569
Re: Gas Cap/tank Question....

What makes you think you need a sealed cap? This is not the 1950's where OMC had a pressurized fuel system with two hoses between the tank and engine because they weren't smart enough to figure out how to add a fuel pump.

With the fuel pump sucking fuel out of the tank and no air to replace it you are creating a vacuum. The vacuum resists the ability of the fuel pump to pump fuel. So guess what. You run out of gas when your tank could be full.

Mark
 

MASTERBrian

Petty Officer 3rd Class
Joined
Apr 16, 2011
Messages
84
Re: Gas Cap/tank Question....

What makes you think you need a sealed cap? This is not the 1950's where OMC had a pressurized fuel system with two hoses between the tank and engine because they weren't smart enough to figure out how to add a fuel pump.

With the fuel pump sucking fuel out of the tank and no air to replace it you are creating a vacuum. The vacuum resists the ability of the fuel pump to pump fuel. So guess what. You run out of gas when your tank could be full.

Mark

Mark, I actually had wondered about that. I guess the reason I ask is that the cap I have appears to have had a vent, but there is a screw sticking in the top, where that hole is. My guess is the vent broke and the previous owner, trying to avoid spending $80 on a new cap, just used the screw replace it. When the plastic cover over the gauge broke on me during my test run, bought the boat knowing it needed some work, the boat seemed to run worse. I'm not sure if that was due to direly needing a carb job, which is on table tonight, or if it was do to the tank not being pressurized any longer.
 
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