Mercury Black Max 150hp outboard making weird sound

[Theaustinhill]

i have an 1980 something mercury black max and when we started it it was making a weird noise. Any ideas what it could be? Also can anyone pinpoint the year of the motor? Ran the serial number and can’t find it.

 

[Theaustinhill]

View attachment IMG_0674.MOV
View attachment IMG_0673.MOV

 

[Chris1956]

That is a 1993, if the decals are original to the motor. I do not like the sound of it, but am unsure what the issue is. Maybe a knock?

Make sure the spark plug wires are on the correct plugs. Pull the cowling and see if anything is amiss. Starter turning, something loose.

You may need to pull the spark plugs and turn it over by hand feeling for any rough spots.

 

[racerone]

This sounds expensive------Pull cylinder heads and look for issues with bad bearings.

 

[Gibbonbon]

A very awesome blog post. We are really grateful for your blog post. You will find a lot of approaches after visiting your post.

 

[jimmbo]

The Decal looks like an early 80s one, could be an 83

That knock sounds Expensive
Did someone drill a Hole in the Exhaust Housing figuring they would gain a Bunch of Horse Power? I ask, cause the engine doesn't sound like it is running fast enough to be forcing the Exhaust down and out the Prop, and Exhaust Relief is just below the Cowl

 

[Gibbonbon]

That is a 1993, if the decals are original to the motor. I do not like the sound of it, but am unsure what the issue is. Maybe a knock?

Make sure the spark plug wires are on the correct plugs. Pull the cowling and see if anything is amiss. Starter turning, something loose.

You may need to pull the spark plugs and turn it over by hand feeling for any rough spots.

This is what I was exactly searching for.Thanks for such post and please keep it up.




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