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| Author |
Message |
    
Brent
Visitor
| | Posted on Monday, June 12, 2006 - 09:18 am: | 
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I just tried starting my P-60 yesterday. It turned over, but wouldn't start. I suspect the fuel isn't getting to the carburetor.
The gas line enters the tank from the top, so when I replaced the fuel filter & pump, I lost the gravity feed. I didn't think it would be much of a problem; figured the fuel pump would be able to generate enough suction to get the fuel flowing again.
However, that doesn't seem to be happening. The pump works - I hear the click, click, click - but I'm rethinking my original logic, and I don't think it has enough suction to get the fuel over the hump and get the help from gravity.
Suggestions? |
Richard Shapiro
Member
Username: mainesails
Post Number: 14
Registered: 09-2005
| | Posted on Monday, June 12, 2006 - 09:26 am: |
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I have an outboard style fuel bulb as close as possible to the tank while still convenient to get to (about 2' down the line in my case). I prime the engine with that.
Because my fuel pump is wired to run only when the oil pressure is up, I HAVE to prime the engine with the bulb. |
Howard Taylor
New member
Username: catec
Post Number: 2
Registered: 01-2006
| | Posted on Monday, June 12, 2006 - 11:53 am: |
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Brent, Remove the gas line to the carb to see if fuel is flowing when the fuel pump is running; if not, the following is probably the problem:
Many installations are supplied with an electric fuel shut-off valve so as to prevent siphoning of fuel to the carb. If this is "off" because of a broken wire or poor connection, fuel will not flow.
OR You may have a clogged suction line.
OR You may have a faulty fuel pump. |
Brent
Visitor
| | Posted on Monday, June 12, 2006 - 12:33 pm: |
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I've no cut-off valve (considered installing one, but decided against it for now).
The pump is new, but I'll check that.
Thought about the bulb, but I'm not quite sure where to install it. The gas line to the separator filter is all metal. I could put it after the fiter/before the pump, but that is down low in the engine compartment. Are those bulbs rated for engine rooms?
I wonder...would some air pressure at the tank work, i.e., pumping some air into the fuel fill? |
J.B. Castagnos
Senior Member
Username: jb_castagnos
Post Number: 138
Registered: 07-2002
| | Posted on Monday, June 12, 2006 - 06:50 pm: |
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Be sure the pump is installed correctly, you may be blowing bubbles in the tank. Get a vacuum gauge and see if the pump pulls a vacuum,at least 5", if not it's defective. Next look for an air leak on the suction side, then a blockage in the tank. |
Richard Shapiro
Member
Username: mainesails
Post Number: 15
Registered: 09-2005
| | Posted on Monday, June 12, 2006 - 09:58 pm: |
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NO!!! Don't pressurize your tank! Tanks, when new are only tested to 3-5 psi (depending on usage). An old tank may have almost no pressure resistance before rupturing. Even if the tank is still good as new, if your source of air is over 3psi, it is far too easy to overdo it! Think about the surface area of your tank, and multiply by 3psi. That's 432 lbs of force on each square foot of tank surface!
On my boat, I ran a rubber line up from the tank to the lazarette, where it goes through the shut-off valve, the bulb, then back down into the engine room and to the separator, pump and motor.
In my case, this was a no-brainer because the tank rests on the forward side of the lazarette bulkhead, which already had a large access hole in it. I just routed a couple of feet of hose.
If you wanted, you could replace the metal line with a rubber one, and bring it to a reachable spot, then return it to the separator.
Also, if the tank is above the carb, I consider a shut-off valve an absolute safety requirement. Otherwise, a piece of crap in your carb float seat and you have your entire gas supply siphoned into your bilge. |
J.B. Castagnos
Senior Member
Username: jb_castagnos
Post Number: 139
Registered: 07-2002
| | Posted on Monday, June 12, 2006 - 10:35 pm: |
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In the 70's Chrysler autos and others used an inline filter with a third fitting to return vapor. I used these on industrial aplications with electric pumps to help prevent over pressurizing. If you would install one of these in the discharge line above the top of the fuel tank level and run the return into the top of the tank it would act as a siphon break. |
Brent
Visitor
| | Posted on Tuesday, June 13, 2006 - 05:22 pm: |
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SUCCESS!
Got the engine started today and let her idle for a good 5-10 minutes to warm up and flush the system with fresh water.
The last obstacles were...
1) A fuel valve that I had forgotten. There are two on my Marshall 22; one at the tank and one next to the fuel filter. I had forgotten about the one near the tank, which was starving her. Once opened, the fuel pump DID have enough umph to self-prime. And...
2) Crossed wires. I thought I was being smart by following the wiring diagram in the engine manual. However, I was reminded that those diagrams are only diagrams. When turning the engine by hand to make sure everything worked, I noticed that I had the 2 and 4 cylinder wires backwards.
Once I corrected these minor issues, and played with the choke a bit, she fired up. A little more play with the choke and throttle and she settled down into a high (800-1000 rpm) idle.
Unfortunately, all this happened about 30 minutes after the boatyard closed, so I won't be able to call them until tomorrow  but with any luck, I'll be overboard for Father's Day!
Now I've got a mad dash to finish getting everything aboard, connect the cooling hoses, etc. |
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