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1977 150hp melted switch box

K

KirkM

New member
Hi,
I just purchased a 1977 150hp. It starts up and seems to run great. I pulled the cowling off and discovered that the switch box, with 4 wires on one side, and 3 on the other, looks like it has melted. There is a rubber material stringing off it and onto other engine parts. What could have caused this, and do I need to replace it? From what I have found online. They are expensive.

Thanks,
Kirk
 
They are not expensive and are easy to install at home no need for a $120 / hr shop.-----So what is your motor doing /. not doing ?----Have you done a compression test ? ----Replaced the water pump impeller ?
 
I was looking at part number 332-2986a21. The cheapest I saw was around $350. Maybe that is not the correct part. It is the box that has 4 mounting screws behind the front cowling cover. I have the new impeller and lower unit oil to put in. I have not done a compression test. It started with the muffs on and ran smoothly.

Kirk
 
Is there a new part that replaces it? I see another item with the same part number that also has a coil on it.

Kirk
 
I still cannot find the part for less than $295. Does anyone have a part number for a lower cost switch box?

Thanks again,
Kirk
 
Try a marina, there are ones near me that will sell used functioning parts or, an old Merc parts salvage company. You could probably get a couple for $300. If it has 1 switchbox it is an inline 6 in 1977. You could also buy a parts motor and have spares for life.
They made 3 switchboxes 1 is for the 3cyl., 1 is for the 4cyl, and 1 for the 6's I'm certain that the difference in them is for the tach pulses.
Here's a wiring diagram of the system for a MerCruiser sterndrive that shows the switchbox internals.
tbolt.jpg
 
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I wouldn't - I go boating miles away from my cottage and can't count on someone towing me home, I don't know about you; there's a possibility that the unit could catch fire and then you're in real trouble, a boat can burn down to the waterline fast.
 
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