Lost gas cap

[ax1lla]

Hello,

So, I was an idiot and left my gas cap on the back of the boat after putting in my 2 cycle. So...it's gone. Is there a trick to knowing what size I need without having to take the boat into a shop? Any advice would be appreciated.

Thanks!

Corey

 

[GA_Boater]

Yes - There is a trick and you missed it.

 

[alldodge]

Would need more then "lost my cap" but look at the fitting to see if it says something like attwood or other on or under it. Measure the opening and the size hose (assuming permanent tank and not portable). Then look on line for one that looks like it. Boat manufactures normally don't make them, they buy from another source

 

[ax1lla]

"So, I was an idiot and left my gas cap on the back of the boat"

You need more than this? I lost my gas cap.I need a replacement. It's a 1974 Sterncraft if that helps?

GA Boater....not sure how you are a moderator with a D#@$ response like that. But, gas caps come in different sizes and the threads can be different. I wanted to know if there was a way to measure that....

 

[Silvertip]

First, 1974 is, according to my math, 45 years ago. Boats of that era, and even many today do not have replacement parts books to check for part numbers. Be realistic here. The first thing to check is your memory. What did the original cap look like. Was it a standard one quarter turn cap like gas caps on older cars, or was it a threaded, screw in style? Then look at the fuel filler and verify your memory. Is it threaded or not. Next, measure the opening. Next, as was suggested, look for manufacturer markings.Armed with this information do internet searches for "Vintage boat fuel filler caps" or similar words. In less than 30 seconds I turned up dozens of fuel caps complete with pictures. As a last resort, you can replace the fuel filler neck which would be supplied with new cap.

 

[MTboatguy]

I have to say, just telling us that you left your gas cap on the back of the boat is pretty vague. There have been a lot of gas tanks and caps in all kinds of different sizes made in the last 46 years. Is it a built in tank, metal portable tank, what brand of engine sometimes the boat will still have manufacture tanks with them. Short of that, use a tape measure to get the diameter and count the threads when the cap screws on. once you have that information start calling the various service depts at marine stores around you.

By the way, if you notice, you didn't mention the boat, the year or what style of tank it was in your first post at all.

 

[GA_Boater]

You got the same amount of info you gave us - Nothing.

A pic or built-in or portable - Anything to help us help you. We aren't clairvoyant.

A screw-in for a 1974 Sterncraft - We're getting closer. Plastic or metal? Lay a ruler across the opening for a starting place.

If worse comes to worse, you may need to replace the whole thing or if you have some boating friends, try their caps.

 

[ax1lla]

OK, I apologize for not being descriptive. Being in IT...I should know better. However, I was more looking for advice on how to measure the threads/opening to determine what to search for. Regardless, I appreciate the fact that people need to remind me to give them more information. Here is some more info:

1. The boat is a 1974 Sterncraft
2. It has a portable gas tank that I just installed last year, along with a new filler
3. I see no manufacturer marks on it
4. It is a threaded screw in cap
5. The engine is the Mercury 1150 (tower of Power)
6. Photo attached.

I have zero desire to reinstall a new filler (just did it last year). In hindsight I should have simply replaced with a newer filler neck while I was installing new tank. Oh well.

Let me know if there is any more info I can provide. And thanks for the help.

Corey

 

[Scott Danforth]

for a built in tank for gasoline, its a 1-1/2" fill neck. however all manufacturers do their own thing on the threads.

it could be a perko based on the pic, however after 45 years the old models were superceeded by new models. so the new perko fuel cap may not work.

not to mention a cap is only a few dollars cheaper than a complete new deck fill.

so buy a new complete filler assembly here on iBoats (or just the cap) https://www.iboats.com/shop/hardware/boat-deck-hardware/boat-deck-fills.html

 

[alldodge]

Could use a measurement across the opening, but it looks like the standard 1 1/4 inch fill cap. Perko makes one, and Seachoice has a chrome replacement. Iboats has the whole fitting, but nothing except yam for cap, found the seachoice cap at walmart

 

[Scott Danforth]

perko cap on iboats https://www.iboats.com/shop/perko-spare-cap.html

you have to use the google search function because the website store search function is hosed.

 

[GA_Boater]

From one D-Head to another :smile:;

When you say you replaced the filler last year, are you saying the cap and filler assembly was new last year? Do you keep receipts and maybe it has a part number?

When you do find a cap, try to get one with chain a or some type of retainer.

One other thing - Did you fill up on the trailer at a gas station? Sometimes when caps are left behind and found, they're tossed in a lost and found box in case customers come back looking. It's worth a shot.

 

[ax1lla]

Thanks guys!

I wish there was a way to know the thread spacing. But, I don't see that as a specification on these various sites. That pic of the perko one looks so similar. I might just order the seachoice one from amazon or Walmart and see if it fits. If not, at least it's an easy return...then I can try the perko one.

I'm not sure the precise names of the parts, but I replaced the gas tank and the filler hose last year. I didn't replace the gas fill plate (not sure if that's the right name.......but I am referring to the part the filler hose fits onto).

 

[Scott Danforth]

so you replaced the hoses, just not the deck fill port. however the deck fill port from 40 years ago would most likely have different threads than the ones now.

again, the USCG standard on fuel deck fills is 1-1/2" hose for gasoline, and 2" for diesel.

i would buy the whole deck fill

 

[GA_Boater]

What size is the hose? That might offer a clue to the cap size of the deck fill.

 

[JimS123]

Measure the diameter of the hole. That's the diameter. Measure the thickness of the threads, count the threads, divide one into the other and thats the threads per inch. That's the spec you need to buy the cap.

Irregardless, the previous advice about the Perko is spot on. Buy two of them because the gas fumes discombomolate the threads and you need to replace it every 8 years or so. I have used that fill for many years.