1956 Johnson FD-10 15hp.

Well got it in the lake. Unsure if its a pump issue or a carb issue. It'll run decent then act like it cant get fuel. If I keep pressure on the primer it'll stay running. Though if I let it run out and stall. I can pull yhe line off the fuel pump and pull it over and its pumping fuel when I pull it over. That sound more like a pump? Or more like potentially a float issue?

You may have a Blockage in, or an internal collapse of the Fuel Line between the Pump and Carb. How old are the Lines?

Brand new fuel line. Brand new primer bulb.

Now my line is like 6-8feet long would that matter? And Ive heard the primer needs to be in a vertical position not laying horizontal. Is that true?

And i found a couple of issues when I got it home.

1. The fresh fuel is no good. Not sure if it was in the tank and I didn't notice or i just got it from the pump but I've got water in my fuel. Not a ton. But it only takes alitte to grief an engine.

2. The carb is definitely needing help. The bowl gasket especially has turned to almost goo and made a mess in the bowl. The float and needle is missing the little keeper that holds the needle to the float. Both the main and idle jets adjustments feel pretty sloped out. I think due to the seals being crappy. Ive got a kit coming.

3. Im suspicious of the fuel pump. It seemed to be pumping okay at the lake. But It wont barely pump when pulling it over at home. I read they won't normally pump at hand cranking speed and only really pump when running? If that's the case then that's pretty much how it behaves. But I ordered one anyway. The longer style not the square.

I was referring to the Line(hose) between the Pump and the Carb. Can look fine on the outside, but be a mess on the inside. I know you added a Fuel Pump, but if the Hose is original, it is 70 yrs old and likely in poor condition. Alcohol in the Gas certainly doesn't help

source of your parts ?----Amazon parts from the ----hooflungdung----Empire?

If the motor is in good shape, then it is worth fixing everything, hoses, fuel pump, carb rebuild etc. Once everything is fixed it will run for years !

jimmbo said:

I was referring to the Line(hose) between the Pump and the Carb. Can look fine on the outside, but be a mess on the inside. I know you added a Fuel Pump, but if the Hose is original, it is 70 yrs old and likely in poor condition. Alcohol in the Gas certainly doesn't help

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Yeah that line checked out good.

racerone said:

source of your parts ?----Amazon parts from the ----hooflungdung----Empire?

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Yes and no. I did order a kit and pump through Amazon. However. I also ordered a Sierra kit for the carb. The Sierra kit is supposed to be here in the morning through O'Reilly's believe it or not.

I can't find a OEM or similar pump. Just rebuild kits.

airshot said:

If the motor is in good shape, then it is worth fixing everything, hoses, fuel pump, carb rebuild etc. Once everything is fixed it will run for years !

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Seems to be. It definitely has to work to push this boat. But I figured it would.

That motor should make the boat fly.-----Listen to folks and find the issues with it.

racerone said:

That motor should make the boat fly.-----Listen to folks and find the issues with it.

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The boats a 14ft crosby sea sled that's had a hard life. I had the boat for a bit and sold it. It resurfaced on marketplace and i got it back cheap. But it now has roll on bed liner on the hull. The rubbery kind. So im sure thats hurting things. Boats rated at 40hp and before the hull got coated the 25hp i had on it did pretty well.

Sorry, my mistake.--Thought it was on a smaller boat.

So I found out going through the carb the low speed needle tip was bent right at the tip. I noticed before it had a tendency to "lean sneeze" or pop back when idled down and it didn't seem like adjusting the low speed did much at all. And there was no seal/packing in there like there is on the high speed needle.

Attempted to clean up that low speed tip best I could. From diagrams it looked to be two little orings or seals used to seal inside so I sourced some from another incomplete carb kit I had from a previous outboard. Felt like they helped seal around the needle shaft.


I made a new bowl gasket today from some thick gasket material. I think i got the contaminated gas all dealt with. And its running decent in the barrel again. Though it still does the same at lower idle and adjusting the low speed needle doesn't change it one way or another.

Im thinking due to the damage im sure is present on the seat surface in the carb and the needle itself I should source another carb?

timing ok ?

That is not a 1956. It looks like a 1957. That type of red cowling with the white stripe was used in 1957 . The red, if you want to properly repaint it , is called Holiday Bronze. I had 3 1957 35 horse horse engines. !957 was the first year that needle bearings were introduced and in 1961 wrote that because of this these engines can run on a 1:50 mix. I never tried it but I did run them with outboard TCW3 instead of 30 weight oil( which was used in those days) with a 1:32 mix and never had a problem.

Are you 100% sure that 1957 was the first year for needle bearings????

racerone said:

Are you 100% sure that 1957 was the first year for needle bearings????

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The 1957 35 horse engines were changed to needle bearings, the smaller engines took longer to see that change. The smaller the engine hp the later they were changed. But the change from 30 weight engine oil to TCW3 allowed the 1`:24 engines to go up to 1:32 although the 1:16 never really did change.

I believe you are WRONG-----The 1949 QD model 10 HP had needle bearings in it.----The early 25 HP had needle bearings as well.

From what I can tell 1956 was the only model year for a 15hp in the 50s and 60s and a 15hp didn't return to the Johnson lineup till 74. At least that's what I can tell from sites showing s 15hp in 56 then a gap till 74.

I'm sticking with 24:1 for now.