1957 18hp fuel pump conversion issues.

I followed this article "http://www.duckworksmagazine.com/05/columns/max/5/index.cfm" to the letter to convert a new to me 1957 18 to a fuel pump. So I took the boat out with it for the first time. Mind you it ran great in a barrel for an hour prior to this. I left the ramp and took off for about a mile all the while running great at wide open. Then it just fell on its face and died. I checked all connections for leaks and all was tight. The glass filter bowl remained full. I can get the motor to run and stay wide open as long as I pump the primer bulb. I pulled the fuel feed line to the carb while it was running and the pump was squirting, just not alot of psi. at idle. Any thoughts? Could a sticky needle valve in the carb be causing this? Help!! Also the mikuni pump part#DF44-211-D flows 14 liters per hr. if that helps

Re: 1957 18hp fuel pump conversion issues.

Look for crimped hoses. Otherwise classic symptom of bad fuel pump.
JBJ

Re: 1957 18hp fuel pump conversion issues.

Yeah was the pump new or used?

Re: 1957 18hp fuel pump conversion issues.

Just bought the pump so its new. No kinks in the hoses either. Im wondering if the sealer I used to block off the vac passage under the reed plate let loose. would that cause this symtom?

Re: 1957 18hp fuel pump conversion issues.

Ill offer this advice. I have done many conversions. I do not like messing with the intake manifold UNLESS it is for a 5.5hp. ANY other motor I tap a barb into the bypass cover for the pulse line, and block the existing pressure supply off by simply sticking a proper sized bolt into 6" or so of fuel line coming from the barb. Job done and no issues guaranteed unless the pump is shot.

Re: 1957 18hp fuel pump conversion issues.

If I tap into the bypass cover do I need to put the little rubber check valves back in on the reed plate or does that not matter anymore? Also, on the vacumn side of the pump it holds vacumn, so would that mean the fuel pump is good?

Re: 1957 18hp fuel pump conversion issues.

I would put the check valves back in and plug the hose like High Trim said.

How old is your gas line and bulb. I have seen them break down and collapse on the inside and the outside still looks fine.

Re: 1957 18hp fuel pump conversion issues.

I would say the fuel hose is in decent shape. I ran my 5 1/2 horse on it the day before swapping on the 18. Ok, will put the valve back in. and drill the cover.

Re: 1957 18hp fuel pump conversion issues.

I did find the problem. The sealer I used (permatex hardening) Failed and came out of the passage that was to stay plugged. So I cleaned out all that and reinstalled the valves. I drilled and tapped the bypass cover and bingo. Pumps fuel perfectly. On with the show... Thanks for the help

Re: 1957 18hp fuel pump conversion issues.

No sweat enjoy the water!