Holley 4160 bowl screws stuck

Jeff,
Have you tried an impact on it? Even though the Phillips head looks pretty bad, it may work. If not, then yes, cut the head off.

Is that carb off your 78? Yes, it looks like someone's been hacking since I notice the fuel inlet is a hose barb and not the USCG required flare fitting used to connect a steel fuel line from the pump. You mention you are concerned about safety but even if you weren't, it needs to be addressed!

Is the carb marine?

All of the bolts that hold the bowls on the carb body should be the long ones like the two you have laying in the photo. I don't think that the short phillips head screw that is laying next to the bolts and the one that is (I assume is stuck) on the right/lower side of float bowl, have any place on that carburetor. The bolts need to run all the way through the carb, metering block and into the carb body. The two phillips head screws shown in the picture couldn't have been doing anything other than plugging the holes that the bolts should go through. If you're putting things back together, I'd suggest using these NYLON WASHERS under the bolts. They will allow you to remove the bolts easily in the future and will re-seal rather than break apart like the fiber type that is usually used. If you plan on doing any work/ cleaning of the carb, using the "blue" reusable gaskets is worthwhile as well. You can find those HERE

As Pete mentioned, you should also look at a regulation fuel line to replace the rubber hose that appears to be connecting the carb to your fuel pump.

Those Phillips headed ones look just like the the ones I had on 3 older Holley's, they thread into a spring which is held in on the other end by a stud. The newer style seems so much easier to work with and when used with the nylon gaskets it's even better. Use the impact by hand first if the bit still fits, sometimes a good bit and a better grip than using a screwdriver will work. Not being at mine to check,many do use 2 different lengths of screws. I'm thinking the primary side uses the longer because of the metering plate that holds the power valve is quite thick.

I would NOT even attempt to cut the head off.   Only if it was the very last option.
As mentioned above a new phillips bit and some impact, maybe get some acetone/atf in on the screw for a day or two.
And get and follow the torque specs from Holley.
Over torquing could be the reason for the old style spring loaded bowl screws.

If you do wind-up with only the last option. Drill the head off, don't cut it off.

Make sure you blow out all the passages with compressed air and carb cleaner.

Those bolts were used for a while. Good idea to replace them with the current style.

183.558 Hoses and connections.
(a) Each hose used between the fuel pump and the carburetor must be "USCG Type A1"
hose*

I'm with you on this one Ken. I have been reading up on this also as I am getting ready to order my fuel system components and was leaning toward using hose rather than solid line. I thought maybe I missed seeing the part that states you have to use solid line to be compliant.

https://www.gpo.gov/fdsys/pkg/CFR-2011-title33-vol2/pdf/CFR-2011-title33-vol2-sec183-558.pdf

Pete

You must have forgot to read the second link so here it is again.

Pay special attention to section 183.560 on page 950.or you can continue to the same section of the first link and they even give examples

After that you can give people your OPINION on what's best instead of a misleading answer on what's legal.

KenO

KenO[/QUOTE]
Ken,
I have read them and then again today. I trust the actual government regulation that has a statement "(d) Not depend solely on the spring tension of the clamp for compressive force" rather than the vague publication by the .American Boat & Yacht Council, [/QUOTE]

Nothing vague about it. They even show pictures of what you can and can't use.

Can't use the little spring type clamps that depend only on the springs pressure

I guess you know more than the USCG and the ABYC.

Pete's big enough to fight his own battles but I must add that I think this regulation has been changed recently. Being in the Key's there is more law enforcement afloat than anywhere I have ever been. I wanted to have the Coast Guard Auxiliary do a boat inspection so I could get the decal saying I'm in compliance since if there are 2 boats out and one has the sticker,it's the one that doesn't that will get singled out. Anyway I had looked up the regs sometime around October when I was getting things together to do a carb and manifold change. At the time it said hard line or a coast guard approved flex hose.

I'm pretty much done down here for the season Ken I have to take it out in a week and put everything away. But I will next fall because I do want it checked out. While you can never be too safe when it comes to this I do wonder how the CG came up with the spec's. I'm running an Aeroquip AN hose assembly on my Mustang. Developed for army navy aircraft it was not approved before. Maybe now it is

JPass

What you found is the same thing that I put a link up for yesterday. It's the first of the 2 links in that post

Gary

I know what I think the answer is to your Aeroquip question, but it's only what I think and neither me or you or plenty of other people would like that answer. I think the fittings are fine but the hose doesn't have those magic words printed on it..

KenO

Interesting read from the posted USCG regs. I have to say that I would interpret them to say that an A1 type hose is perfectly fine to use legally.

I also think that there are more modern materials and connections that are far superior to anything that is official USCG approved. AN type hose and connections immediately come to mind.

As for the OP and his carb, I have to say that it's amazing that carb runs as well as he said it did. We often hear and see carbs that have the smallest particle of dirt really mess it up. The way that carb looks, I'm surprised it ran at all, let alone run good.
I've seen that spring/screw setup on marine carbs before and I agree with others that replacing those with the more traditional full length bolts and nylon washers is the way to go.
And for God's sake clean that thing up.....LOL.

Back again with the answer I got from the ABYC technical standards department.

USCG A1-15 hose used in conjunction with barbed fittings and proper hose clamps is in accordance with the USCG regs.

The links I posted earlier to the USCG reg and to the ABYC guideline on how to comply with the regulations are both the latest versions.

The guideline is easy to understand and gives specific examples of the type of clamps than can and can't be used so the average person (that would be me) can be in compliance.

The wording is straightforward and there is a ton of information on fuel systems in it.

KenO

Just trying to keep us all informed Pete

backfoot100 wrote: I also think that there are more modern materials and connections that are far superior to anything that is official USCG approved. AN type hose and connections immediately come to mind.

I have AN lines and fittings all over my boats but I don't agree with the AN type hose as being superior to the A1 rated fuel line, at least not when it comes to flammability. The A1 stuff will withstand fire and high temperature much longer than the AN hoses I have bought.   I tested with direct flame sources, hard to tell if the stainless braiding would offer any protection in a more real world situation but it doesn't help much with a direct flame test.. the AN stuff lasted about as long as standard Automotive fuel line. The A1 rated fuel hose I had was a whole different ball park.