Tach for 1993 75hp Mariner doesn't work!!

[Big Buck Buster]

Will do.

Are the pumps that hard to replace on these newer motors? I have had some older merc's that were pretty easy to replace.

[boatfixer]

Quite easy if you have done it before. I'd even say easier. High volume impellers are easier to work with, water tube doesnt move all over when reinstalling the lower unit. Engine tilts up further so you dont fight gravity as much.

[Big Buck Buster]

That is great to hear.

Will have to see the next trip.

What temp is good when checking the heads with the temp gun?

With a bad impeller, will one cylinder run hotter than the other two, or will you see an increase from cylinder to cylinder further from the pump?

[boatfixer]

I look to see if it continues to heat up. If you start getting to 150-160 (kind of an arbitrary number) at idle and it keeps climbing, thats a good indication. If it is worn, the top cylinder will be warmer. I wanna say the temp sender is somwhere around 190

[Big Buck Buster]

Thanks again for the info.

No more question for now.

I might just replace it anyway. Cheap investment for precautionary measures.

[Big Buck Buster]

Thanks for all the help!