what phat said

What phat and spare and steplift says. By removing or breaking the seal on the cap it will proved air to flow in, if it does than I would check out the vent. Could be crimped,kinked or blocked. If it make no change than I would look in the fuel tank for blockage. You can use a portable tank and see if that fixes the problem , if it does than its in the tank or hose going into the tank ,if it stays the same I would change the bulb and the lines if it's not hard. But I would wait for spareparts or phat says. I hope they would agree eight me if not than I will listen to them. We want to get you home safe and have a happy boat,

I tried to run it with the gas cap off and it made no difference. I’m still going to address the vent because It’s 30 years old and for the few bucks, it’s another thing that could crap everything up.
You guys figure the fuel line to be 3/8” or 5/16”? I cut an inch off when we first pumped the tank but I can’t find any writing on it.

As far as changing out the fuel line if it’s not hard… IT’S HARD!!!! But if I don’t, my season’s over. I’m not ready to pull her out for the season. I missed a lot of fishing being without a boat for close to 10 years.

Hey Charlie , before you change the fuel line , did you change the primer bulb? Cause I feel that if its callapsing inside the bulb that would cause it. How old is the bulb? Do you know how old the line it? I dought its the vent since you removed the cap and no differance . Go for the simplest thing first..... The bulb. If you can get a hold of a portable tank. Try useing that and see if the problem goes away. I would wait to see what the big guns say .
I'm just thinking, something is blocking the flow, maybe the pickup tube in the tank is getting blocked, I don't know if there is a screen on the end of the tube that in the tank, see what the phat and spare say .

step, no clue how old anything is. somehow, whoever installed or changed out put the bulb in so there's absolutely no extra play in the fuel line. the bulb is way down inside the fishbox, between the inner wall of the transom well and the batteries. it's a real ***** getting a hand down in there even to squeeze the bulb. changing it out without doing the fuel line seems almost impossible. maybe 20 years ago, or even just a few years back when i could still do some mechanical yoga.... at this point and approaching 60 years old, if doing more will actually be easier, and for the few extra buck for fuel line i figure what have i got to lose. it'll be less work for me to change out more in this case.
i didn't even think of running it off the auxiliary tank. i'll try that over the next couple days before i start ripping everything out.

I know it's a pain in the ash. But that would tell you more if you use a portable tank. It's going to tell you that your issue is somewhere in the fuel delivery what I would do in this order is Ask Spareparts lol.
If it runs good on a portable tank the next step that I would do is replace the primer bulb with a Mercury bulb. True it's more money but it's worth it.
Next I've you still have a issue I would take the pickup tube out and check it for blockage, buy wait a secound it just came to me, do you have a water sepperator? If yes. Change that first cause that would cause you to lose power ,, but next change the inline fuel filter too. I would do that definitely first if you have a water/ fuel filter, it looks like a cars oil filter. Good luck. I will be watching for a post.

Plan on changing the filter/water separator. Don’t know if or where an in-line filter may be hiding. I’m basically gonna take everything apart from the anti siphon to the motor. The way I figure, most of that crap must be 30 years old. For the $100 bucks it’ll cost me… I figure I’ll cover Everything as far as fuel delivery. If that doesn’t solve my problem, then I sink her.

So I went down to the marina yesterday and pulled the tank hatch up. I sprayed some WD-40 on the fitting because I forgot to bring the liquid wrench. I’ll take it with me today and spray the fitting again. I’ll bring a wrench with me and see if I can budge it. If not, I’ll go down tomorrow and spray it again. Then, I’ll spray it every day for a week and see if it’ll budge after that. I figure if I spray it for 10 days, something’s gotta give. When I settle in for the evening I’ll order the primer bulb and the fuel/water separator filter. I’ll measure up the fuel line and run to west marine. They’re about 5-6 miles from my front door. When I get the fitting/anti siphon valve off and see what size it is, I’ll order that up and by that time, I figure I’ll be in for around $150. The real ***** is gonna be yanking the batteries out for unrestricted access.
Oh well, here comes boat mechanic’s yoga.
I’ll keep you guys posted and I’ll try to paint a mental picture because we all know what a pain in the a$$ it is to actually post a picture.

So the bulb is now inside the fish box area with the filter and the batteries. Kind of tight in there and there’s really no slack in the line. It’s kind of between a battery and the inner transom well. Is there any real advantage or disadvantage to relocating it to the transom well? Yes, it will be more convenient. What’s the down side?