Johnson 10 hp Seahorse won't stay running.

[Stangfire5]

I have a 1960 Seahorse 10hp. Model QD-21.

It runs fine if I keep squezing the fuel line ball every 5 seconds. As soon as I let it run on it's own it bang's/sputter's and stalls.

I've cleaned the carb, new fuel line's, tried two different fuel tanks.

I think it must be the fuel pump. Is there any online diagrams for it? I know it comes apart and I think it's vacum powered.

Also what should I set the two carb mixture screw's to when starting out after taking the carb apart? There is a little one at the top of the carb and a larger one at the bottom.

A diagram of the carb would also be nice to have.

Thanks,

Chris.

 

[F_R]

Re: Johnson 10 hp Seahorse won't stay running.

A QD-12 is a 1951 and did not have a fuel pump but a pressurized gas tank. Since you obvioulsy have a pump and squeeze bulb, it has been converted. Next question is HOW it was converted. If it has the pump mounted on the bypass cover on the side of the motor, that's good. Whether the pump can be repaired depends on which pump you have. Some can be and some cannot. But all can be replaced. They have them here at iboats.

However if you have a pump that is mounted in any other way, it has been cobbled up and you are on your own.

 

[Stangfire5]

Re: Johnson 10 hp Seahorse won't stay running.

What fuel mixture should I run? Currently I'm running 50:1

 

[F_R]

Re: Johnson 10 hp Seahorse won't stay running.

24:1. Those engines beat the wrist pins out of the pistons bad enough without starving it for oil yet.

 

[Stangfire5]

Re: Johnson 10 hp Seahorse won't stay running.

I'm going to have to double check the serial & model number. It doesn't look anything like a 1951. It looks more like a 1960. (I searched the net for pictures)

I think the model number was OD-12 not QD-12 and I know the serial number had 666 in the middle part of the number. (can't remember the rest right now)

I'm also very positive that the fuel pump is stock and not added on.

Thanks.

 

[BoatBuoy]

Re: Johnson 10 hp Seahorse won't stay running.

This is all the 10-horse Johnson built. Take your pick:
Year Model
1949-50 QD-10
QD-11
1951-52 QD-12
QD-13
1953 QD-14
1954 QD-15
1955 QD-16
1956 QD-17
1957 QD-QDL-18
1958 QD-QDL-19
1959 QD-QDL-20
1960 QD-QDL-21
1961 QD-QDL-22
1962 QD-QDL-23
1963 QD-QDL-24

Could dyslexia have kicked in, maybe QD-21?

 

[Stangfire5]

Re: Johnson 10 hp Seahorse won't stay running.

Opps, the model number is QD-21 therefore being a 1960.

Anyone have an online diagram of the fuel pump for a 1960 10hp seahorse? I found a carb diagram.

Does my stalling problem sould like a faulty fuel pump?

Sorry for the confusion, I was working from memory.

 

[F_R]

Re: Johnson 10 hp Seahorse won't stay running.

Could be the fuel pump. Or it could be sucking air somewhere between the tank and fuel pump. Or even the tank itself if it is the original with the two little pins that get pushed in when you plug on the hose.

Not 100% sure, but I don't think the 1960 fuel pump was repairable. Well, it WAS but they quit making parts for it about 40 years ago. I have a couple of those pumps in my shop which don't work and can't find a diaphragm for them. However, your pump may have been replaced sometime in the past. No way of knowing which you have without a picture or something.

Best to just break down and buy a new pump and be done with it. They have them right here at iboats. Part number 18-7351