merc overheat

[merc8978]

1990 merc 4.3 L w/thunderbolt 4 ignition w/ alpha 1

I have a condition where the engine starts up fine and will run till warmed up then stall until cool again.

i have noticed that the elbow with amplifier is much hotter than the other one indicating a blockage?
does the ignition amplifier attached to exhaust elbow get too hot and temporarily stall engine until it is cooled down?

I loosened amplifier mount to separate from elbow and it seemed to cool down and engine started up to get home

I will have to replace elbow anyway but wondered if it could react this way.

 

[Bondo]

Re: merc overheat

Ayuh,..... It's entirely Possible...........

 

[bamafutbal]

Re: merc overheat

sounds like mine. i then replaced the impellar, even though it looked new at 2 years of age. problem not fixed, then i changed both risers and manifolds and problem not fixed. now i am changing water pump and thermostat, hopefully that will fix it. good luck, from my one and only experience is to just change it all

 

[merc8978]

Re: merc overheat

impeller is new - temp. guage is fine - engine is running within spec.
i just hate throwing money at it to solve a problem - prefer the diagnose and test method

 

[Bondo]

Re: merc overheat

prefer the diagnose and test method

Ayuh,..... Then go out,+ Run it.....

When it Quits,.... Check to see if it's Missing it's Spark, or Fuel.....

If it's the Fire,.....
There's a diagnostic tree in the Factory Manual to find Exactly Where it's loosing it's Fire.....

 

[merc8978]

Re: merc overheat

is the #18 manual good for my 4.3?
it seems the year is not covered.

 

[Bondo]

Re: merc overheat

Ayuh,.....

Even though the manual #18 is for an earlier vintage,....
Very, Very little changed between them......