carb adjustment question

My local Holley dealer has heard a rumor about marine pumps(recent) putting out too much pressure...

Possible diaphram material change?

Dave,
Have we asked you for pictures yet? We'd love them!

I'm glad to hear the rebuild went great.

This online place is great. I have learned an incredible amount of information, and finally have a chance to give back something that may be useful.

I needed a rebuild of my engine because when I was winterizing, I was poured Sea Breeze (liquid, not spray) through through the carb of the cranking engine in an effort to distribute the oil to all cylinders. I ended up withe oil in the lowest cylinder hydrolocking and bending the connecting rod.

I thought I was being careful but the oil flowed down the intake manifold, through the intake valve and into the lowest cylinder, causing the connecting rod to bend and the piston to hit the crankshaft. (The clearance between the descending piston and throws of the crank had decreased enough for this to happen.) I had to replace the piston, rings, rod, bearing, but did not requires any bore work.

I had a highly recommended marine engine shop (Berger Machine and Marine, Hagerstown. MD), tear it down and was curious what they found in a 24 year old engine with about 900 hours. To me, it was very encouraging: virtually no cam wear (I have been careful about the oil) , no significant wear/burning on the valves to requires head machining (the carb is jetted to be slightly rich), very little bore wear (I had suggested re-ringing if at all indicated), new ring gear because of some substantial teeth wear/chipping from starter, new cap, rotor and all gaskets. Also all dash instruments were erratic. Total cost: Labor $1834, parts $289. They did not work on the electrical issues, but checked oil pressure/temp with shop gauges.

The gauges went wonky on me last summer, so more under dash work this spring, probably cleaning up grounds.

The carb dripping issue was solved before all this happened.

Hope this information might be useful to others, especially the part about pouring in the winterizing oil.

Dave

Pete,

Good thoughts and I will look at this again.

I just rebuilt the motor (from too fast/too much pouring winterizing oil through the carb and bending the connecting rod) Ahhhhhh!!!. The inboard marine shop that did the work nit picked about several items in my engine compartment, mostly insufficiently unsecured wires, none safety related, but did not mention this.

I bought my hose from a Correct Craft dealer who said they were using the flexible fuel hose on their boats. I checked the procedure with Holley, their marine guy, who insisted that I double clamp the hose/nipple connections.

Now you have me thinking, what would be pressure be on the pump side of the regulator? Since there is a provision for checking this on a vacuum gauge (I am wondering how accurate.....) I will check this. I am thinking that it can't be too high, because the fuel pump came from Ski Dim, for the 1988 351W and most of those engines never had regulators. The fuel line is heavy, and the connections are secure. Still, if you had a fire, a hard line would seem to be better.

Thanks again for pointing this out.

Dave

pdhowell wrote: Snipe, you got me thinking about this this morning. I replaced the hard line from the pump to the carburetor with a flexible, rubber fuel line made for marine use. I bought it at a local CC dealer. It was very similar to this: http://www.jamestowndistributors.com/userportal/show_product.do?pid=576&familyName=Fuel+Feed+and+Vent+Hose+Type+A1. That is about the same price I paid per foo, and I think used 1/4 inch line. Marine fuel line has more fabric and seemed much thicker than automotive fuel hose. For connections, I used 1/4 npt barbed nipples screwed into the ports and double hose clamped all the hose/nipple connections. This hose made taking the carb off much easier, since I wasn't always struggling with the threaded fittings on the hard fuel line. Dave

Dave,
Look closely at the description. You used a fuel rated hose designed for the feed side (low pressure) of the fuel pump. The high pressure side from the pump to the carb per USCG regs must be hard piped with flare fittings or a USCG approved hose assembly. You just downgraded your boat to being dangerous. Go back to struggling before you have a problem.

BTW, here's a proper link to the rubber low pressure fuel line

And here's one to the fuel pressure regulator
What pressure were you feeding the carb before you installed the regulator? I ask because somethings wrong. We have hundreds if not more members who haven't needed the regulator?

Dave,
What kind of flexible hose did you use between the fuel pump and carb?

If the float adjustment does not work, you might look at a fuel pressure regulator. I had the same problem on my 1988 PCM 351. A fuel pressure regulator solved the problem. I believe I used this one:   http://www.summitracing.com/parts/HLY-12-804/

I cannot remember, but that I had to cut or replace the hard fuel line with a marine flexible line, but it was an easy install. It goes between the fuel pump and the carburetor.

I was concerned about this being automotive unit , and called the Holley tech folks. They said that this was the same part they used in marine engines.

Maybe useful

Yea I put new needle and seats in even after the rebuild ,I thought I might have got a bad needle or seat. It didn t fix the problem of the rear bowl flooding till I bent the float down a little. I did the same to the front bowl last night. Maybe that will fix the problem.

Thanks

Robbie, I had the same issue with our 96', pulled the flame arrestor after a run, and sure enough fuel was dripping and puddling in the front two bowls. When back at home, took off fuel bowl, adjusted float, and problem solved. Pretty simple fix to an annoying problem.

When you shut it off, remove the flame arrestor and see if it drips or runs fuel down into the motor, if so and is in the front 2 barrels remove front fuel bowl and adjust float level (bend) to lower the fuel level in the bowl, if rear do rear