1956 FD-10L Johnson 15hp Fuel Issue

[Drowned Rat]

Good morning iboats family,

I picked up one of these beauties yesterday and had a question about the carb bowl. The previous owner said that there was fuel leaking from around the glass bowl, so he went to change the gasket that sits above it, but instead of buying the right one, he made one from cork. Now it won't run. When you squeez the bulb with this cork gasket installed, it is very difficult to get the bowl to fill. Does this also mean that the fuel is likely not reaching the cylinders? Becuase the gasket is cork, or perhaps wasn't cut to exacting specs?? I presume it may be blocking the outlet passage to the carb.

Any help with this one? BTW, this motor has had a properly converted fuel pump.

Thanks so much!

 

[HighTrim]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

Great motor. I have the electric start model buried somewhere around here!

I don't see how you could be blocking the outlet passage with the gasket, unless it was cut WAY too big, lol. Filter itself may be clogged. Does it still have the original filter in there? Try taking it out and priming again. The rubber gaskets are cheap, might want to put one in.

 

[Drowned Rat]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

Thanks HighTrim,

I tried removing the filter and running without it and it still wouldn't (or appeared not to) prime. Still difficult to fill the bowl which seems wrong. I do belive it is the original filter. I thought maybe the cork swelled up and blocked something. It looks a tad wider than the rubber version, but I'm not sure cause I'm just looking at pictures. I'll order one and give her a try.

Without removing the carb (which I don't want to do) I can't see underneath where the bowl seats. Where do the inlet and outlet fuel passages enter? There's that flat brass circular nut that holds the filter in position which looks to me like it would block all fuel flow, but obviously it doesn't.

Here's a pic of the gasket he cut, whatcha think? >>>

The outside diameter seems pretty spot on, but the width seems too much...

 

[Drowned Rat]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

BTW, I tried just leaving the gasket out and priming and the bowl fills in a flash then. But of course it leaks. Is that evidence that the gasket to blocking somthing?

 

[racerone]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

A very simple carburetor and no need to be afraid of learning how to inspect / repair / adjust it.----Your local shop likely won't work on it any way.

 

[Drowned Rat]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

Yeah, I just wanted to avoid haveing to replace all the gaskets if I could help it. I'll try the new (correct) bowl gasket first and go from there.

 

[HighTrim]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

The inlet is on the side wall of the cavity. Comes in through the fuel inlet, through the wall, then through the filter, and the outlet is on the top of the cavity into the carb. Well away from the gasket. The gasket sits on a ridge, and the inlet/outlet is well away from both. Ill post pics, I had to tear a carb apart today anyways.

So the fuel flow from the outside of the filter through it to the inside. When I clean them, I like to blow compressed air from the inside of it out to flush out debris.

 

[HighTrim]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

Ok, these should help. You can see where fuel enters from the side in the first pic, then where the fuel outlets into the float bowl on the top in the second. No where near the gasket.

 

[Drowned Rat]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

Ok, I understand. Yes I can see how the gasket should not be a factor then. Perhaps I've got something else going on.

Thanks so much for your time. I'll keep you posted.

 

[HighTrim]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

Maybe a chunk of cork came off the gasket and plugged the passage to the float chamber. I would pull the carb and go through it anyways. I don't trust anyone's works that I don't know. Any new motor to me, I go through the carb, ignition, water pump, etc...before running it.

 

[Drowned Rat]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

Ok, pulled the carb off and found two things of note. First is it's absolutely sparking clean with no gunk or pieces of dirt in the passages. I blew them out with air to be sure, but they were clean. Second thing is, the float bowl was dry as a bone. No fuel has been in there. The only thing that can be blocking that is the float pin correct?? It looks brand new and installed correctly. Please look at this pic, is the float installed correctly?? >>

It's not upside down is it? It wasn't stuck when I removed it, the pin slid in and out with no resistance whatsoever. The glass bowl itself will pressurize with fuel, that's how much pressure is being put on it, but it won't fill up. What could be the problem?

I visually inspected the passage from the fuel inlet to the glass bowl and from there to the float bowl where it encounters the float pin. All clean and clear.

Ideas?

 

[Drowned Rat]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

If the owner did not remove the check valves on the reed plate when he did the fuel pump conversion, would this cause this problem?

 

[racerone]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

In your picture there appears to be a tab sticking up ( shadow thrown ) if so it may be upside down.----More pictures ?-------The check valves have nothing to do with fuel going into the carburetor.

 

[Drowned Rat]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

Hi all,

yep, the dang float was upside down. Flipped it over and the motor started on the second pull. Thanks racerone and High Trim for helping me out!

iboats is the best, as usual.

 

[HighTrim]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

There have been a few upside down floats on the forum lately! Glad you spotted it. Tab always down. They should make it so that it wont even fit upside down.

I just finished up the mechanical restoration on the QD14 that I posted the pic of the carb from. Time to go barrel test it too. I put a fuel pump on it as well. I don't ever mess with the intake manifold though. I always plug the pressure line and get my pulse via the bypass cover.

 

[Drowned Rat]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

I believe that's the way this guy did this motor also. I was just looking at some youtube videos of folks removing the reed plate and plugging certain passages in there. Not sure why that would be necessary. I love these old motors, can't wait to take it to the lake!

Thanks again...

 

[HighTrim]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

It is one way to do it. You then use your old pressure line that went to the fuel fitting as your pulse for your pump. I don't like this technique. It is necessary though on the small hp motors that do not have removable bypass covers unless you pull the whole powerhead apart to do it. If you try to drill and tap the bypass cover in place, you will get shavings into the powerhead.

Unless I absolutely must, I don't touch the intake manifold.

Have fun on the water!

 

[HighTrim]

Re: 1956 FD-10L Johnson 15hp Fuel Issue

It is one way to do it. You then use your old pressure line that went to the fuel fitting as your pulse for your pump. I don't like this technique. It is necessary though on the small hp motors that do not have removable bypass covers unless you pull the whole powerhead apart to do it. If you try to drill and tap the bypass cover in place, you will get shavings into the powerhead.

Unless I absolutely must, I don't touch the intake manifold.

Have fun on the water!