Mercruiser 4.3 tks

[Seapro210wa]

Hi guys I bought a 22 foot walk around with a 4.3l engine in it last year. When I bought it the former owner did a lot of his own work on the boat. He had replaced the carburetor the year before. I ran it all season and it would not go above 25mph and I noticed fuel leaking from behind boat. At the end of the year I dropped it off to have it looked at. They went by the number on the flame arrestor and told me that someone had changed the manifold from a 4 barrel carb to a 2 barrel. I thought this was odd and looked into the records from when it was reported around 2012. Upon discovering the engine block number was different than the number on the flame arrestor. They told me the prior owner had installed the wrong carburetor and they were going to order the correct one which is TKS. They told me the carburetor gaskets are different and that’s why it was leaking fuel. They seemed sure this would solve the problem. When they got it back and started it up they said it was no longer leaking fuel. Upon starting it again they heard a clunk noise which ended up being a bolt from the starter breaking off in the engine block. That’s how my boating season ended last year. They winterized it. Does this sound like it would solve the issue? Also how hard will it be for them to get the bolt out of the block? How many different carburetors are there for a 4.3 carbureted Mercruiser engine? I had never heard of anything like this before. Thanks I’m just wondering just dropped it back off to have the work done and am really hoping to have a great year this year.

 

[alldodge]

Not real sure of all the questions your asking, but will try to answer what I think your asking

There is nothing wrong with the TKS carb, but could also replace it with a Merc 2bbl or Rochester 2GC carb, and would cost less

The ease of getting the broken bolt out all depends on how it broke off. If its flush with the block, then may need to remove the motor. If part of it is sticking out, may be able to grab the end and remove easy

They winterized it. Does this sound like it would solve the issue?

Don't understand the question

 

[Seapro210wa]

Not real sure of all the questions your asking, but will try to answer what I think your asking

There is nothing wrong with the TKS carb, but could also replace it with a Merc 2bbl or Rochester 2GC carb, and would cost less

The ease of getting the broken bolt out all depends on how it broke off. If its flush with the block, then may need to remove the motor. If part of it is sticking out, may be able to grab the end and remove easy



Don't understand the question

Sorry I wasn’t being clear. The prior owner put a 2 barrel carburetor in that was not tks. Apparently it’s gasket is different and that’s why it was leaking fuel and not accelerating to full speed. They removed that carb and installed the TKS one but I never got to take it out and test it because the starter bolt broke off at the dock. I then had them winterize it. I’m just asking if this makes sense that the guy who owned it before installed the wrong carburetor And that is why it wouldn’t run above 35 mph.

 

[Seapro210wa]

Sorry I wasn’t being clear. The prior owner put a 2 barrel carburetor in that was not tks. Apparently it’s gasket is different and that’s why it was leaking fuel and not accelerating to full speed. They removed that carb and installed the TKS one but I never got to take it out and test it because the starter bolt broke off at the dock. I then had them winterize it. I’m just asking if this makes sense that the guy who owned it before installed the wrong carburetor And that is why it wouldn’t run above 35 mph.

Sorry 25mph

 

[alldodge]

Sorry I wasn’t being clear. The prior owner put a 2 barrel carburetor in that was not tks. Apparently it’s gasket is different and that’s why it was leaking fuel and not accelerating to full speed. They removed that carb and installed the TKS one but I never got to take it out and test it because the starter bolt broke off at the dock. I then had them winterize it. I’m just asking if this makes sense that the guy who owned it before installed the wrong carburetor And that is why it wouldn’t run above 25 mph.

Going from a 4bbl to a 2bbl will not make the boat run slow. The 2bbl reduction in HP is not that much. The carb leaking gas could cause the reduction in speed. If you do a compression test it will tell the health of the motor

 

[Seapro210wa]

Going from a 4bbl to a 2bbl will not make the boat run slow. The 2bbl reduction in HP is not that much. The carb leaking gas could cause the reduction in speed. If you do a compression test it will tell the health of the motor

That’s what I’m hoping tha ks

 

[achris]

... How many different carburetors are there for a 4.3 carbureted Mercruiser engine? ...

Depending on the era...
Mercarb (very similar to the Rochester 2GC)
Rochester Quadrajet
Weber 9600 and 9666S
Mercarb TKS (and there are 2 variants of that for the 4.3)