What's this? Off my 1980 20' wellcraft with mercruiser 4.3 engine

[Brian922344]

Inherited this boat halfway through repair and this was one of the parts.
Trying to upload a picture but it won't allow me.

It seems to be a relay.
Black plastic box no writing on it about 1 in dimension on all sides.

was bolted to the top of the thermostat housing.

Has four wires coming up from it;
Two black wires, a white wire and a red wire

 

[ScottinAZ]

most likely exactly what it is, a relay. Red is likely 12v power, white is 12v triggered, and the blacks are grounds. you will need to check the manual for your engine/boat to be 100% sure though

 

[Scott Danforth]

If your boat has a 4.3 in it, it was transplanted.

The 4.3 came out in 1985

 

[Brian922344]

If your boat has a 4.3 in it, it was transplanted.

The 4.3 came out in 1985

https://m.facebook.com/story.php?story_fbid=pfbid027kbZWn7RsGXbevxCVC1ocCPcNCoeGjwcH1w1MKgpjbF6FfVwkBerdy9AiNp2Y59ul&id=100033168756797&mibextid=Nif5oz

 

[Brian922344]

https://m.facebook.com/story.php?story_fbid=pfbid027kbZWn7RsGXbevxCVC1ocCPcNCoeGjwcH1w1MKgpjbF6FfVwkBerdy9AiNp2Y59ul&id=100033168756797&mibextid=Nif5oz

If your boat has a 4.3 in it, it was transplanted.

The 4.3 came out in 1985

My mistake I looked it up 1989
Pictures found here

https://m.facebook.com/story.php?story_fbid=pfbid027kbZWn7RsGXbevxCVC1ocCPcNCoeGjwcH1w1MKgpjbF6FfVwkBerdy9AiNp2Y59ul&id=100033168756797&mibextid=Nif5oz

 

[nola mike]

Not stock, where do the wires connect? Does it have an electric fuel pump?

 

[Brian922344]

Yes it has an electric fuel pump.
Could it possibly be something to do with that?

Here's the link for pictures

https://m.facebook.com/story.php?story_fbid=pfbid0G6wnbJYGJKpiuf8kMG2142B6CJAL1dG6Em4p33CJJSeorBoSdbFyzn4dykthYdgKl&id=100033168756797&mibextid=Nif5oz

 

[nola mike]

That's a possibility, I think the pumps were mechanical until at least the balance shaft engines. I guess trace the wires, or see what your oil pressure switch looks like. Factory switch was 2 terminal, if relay is used it's likely 3 terminal.