Johnson Seahorse 7.5

[Bowshark7595]

Looking for a little advise or tips. I have a 1980 Johnson Seahorse 7.5 that I recently pick up from a neighbor. The motor doesn't appear to have been used that much and seems to be in very good shape.

However, due to the age, the first step was to replace the water pump and lower unit oil before a quick test run to see if it had potential.

The motor fired right up on the third pull with new gas, fuel line, primer bulb, and tank. It ran pretty good. We then went through the carburetor with a complete rebuild kit. The next test run was much better, but she had a little hesitation at mid throttle when accelerating. I figured we still had some kinks to work out.

The third run wasn't so good. She would start right up, but when trying to accelerate at mid throttle, she would die. At one point, it seemed like it wasn't getting gas through the primer bulb, but eventually I think this was resolved.

If I'm able to get pasted mid throttle without it dying, it runs great a full throttle. It will also idle just fine.

I plan to check the fuel lines under the cowling and the screen in the fuel pump to make sure I don't have any trash or blockage. I may go through the carburetor again.

My question is, is there anything else I should be aware of? Any tips or anything else I should check? Why does it seen to choke out when accelerating?

I really appreciate any tips or information.

 

[timguy]

Has there ever been a mouse in there? Any sign of seeds or chewing? Is the carburetor ramp roller okay and riding the stator ramp smoothly? When it dies or stumbles at mid throttle, does pumping the primer bulb help? You can also try raising the fuel tank up on the seat getting it above the carb level. That may create less work for the fuel pump by giving it a siphon help. If these last 2 suggestions work then we can rule out almost everything electronic as well as from the outlet of the fuel pump through to the carb. To rephrase, we will then focus on fuel pump and line to the tank as well as pickup tube within the tank. It is possible that depending on the general condition of the wiring, besides the chance of mouse damage, the wire to the trigger/sensor or exciting coil on your stator is damaged from corrosion. This will effect conductivity of course, in certain throttle positions, thereby interrupting spark. This will get only worse each run you make.

 

[Bowshark7595]

Thanks Timguy! I far as I can tell, there is no mouse damage. All wiring seems to be clean and intact. The ramp roller is running smooth, but I'll double check it. I'll double check the fuel line, bulb and pickup tube also. Because at one time, the primer bulb would not pressure up. I would put a new fuel pump on it, but it appears to be unavailable. I can definitely check the screen. It doesn't sound like any misfire or timing issue is going on. It just gets sluggish and bogs down.