1974 Mercury Thunderbolt 50 HP Bogs down/Shuts off

[Marchosia]

So I recently purchased a boat that has what the registration says is a 74 Mercury Thunderbolt 50 HP. The problem is when its cranked up even if its idling it'll run for a few seconds then just shut off completly, and if i continualy choke it it'll stay on longer but then eventually shut off.. So what is causing it to do this? Does anyone know the solution to this problem?.. Thanks in advance..

 

[Sunfish12]

Re: 1974 Mercury Thunderbolt 50 HP Bogs down/Shuts off

Clean the carbs and rebuild the fuel pump.

 

[hotrod53]

Re: 1974 Mercury Thunderbolt 50 HP Bogs down/Shuts off

Like sunfish12 said.... using the choke chokes off air and richens up the mixture meaning that you are not getting enough fuel. Make sure the fuel tank vent is open and if you have a filter, make sure its not clogged. Fuel pump may be an issue and not delivering fuel, if a rusty metal fuel can was used, maybe your inlet screens are clogged.

 

[duckhunter138]

Re: 1974 Mercury Thunderbolt 50 HP Bogs down/Shuts off

hey had the exact same problem drove me nuts. replaced everything from the fuel tank to the carbs. ended up being the adjustment screws on the carbuerators. turn both of them all the way in then turn them 1 and 1/4 turns out. ran like a dream after that. just make sure your fuel pump is putting out fuel as well and that you have spark. should take care of your problem.

 

[kevblac]

Re: 1974 Mercury Thunderbolt 50 HP Bogs down/Shuts off

I just had the same problem with my 850. I replaced everything! the problem was resolved on the last repair when I replaced all the fuel lines on the engine and rebuilt the carbs. not sure which on actually fixed it, but either way it runs now. Todays fuel eats those old lines up, if your getting any fuel line collapse it will restrict the fuel flow and bog after about half throttle.