My motor is over heating. 2007 3.0L 135HP MercCruiser. There are two blue hoses that are the block drain and some other drain but when I felt the block drain hose today it was extremely hot. Not sure if that is normal. The motor usually stays around 175 but it got up to around 225+ this evening. Any suggestions???

When did you have the impeller or water pump last changed? Was there anything blocking the water intake holes on the lower unit?

Did you have it trimmed up too high?

Trimmed all the way down. Nothing blocking the holes on the lower unit. I bought the boat new last June and have not had the impeller changed.

Well, that will need to be done now that it's gotten hot...Hopefully you didn't do any damage, most likely you didn't, but the impeller will need to be changed and possibly the whole water pump (it's not that expensive and you may be able to do it yourself, depending on your mechanical abilities)...

Water impellers should be changed yearly (or at least every other year) depending on how often they are in use. They actually last longer the more the boat is used (go figure right)...

Opti, a poster on here, might be able to lead you in a better direction, but I'd suspect the impeller/water pump...

What do you consider inexpensive?

Here are some other possibilities...

1. Something got into the impeller, causing it not to turn, sending less than enough water to the engine.

2. Hose coming in from outdrive to engine could be damaged and not able to carry enough water.

3. Hose coming off 'water pump' on the front of the engine is damaged, or the belt is no longer turning properly (doubtful).

4. One of the drain plugs is damaged, or slightly open letting out water (doubtful)...

5. Bad gasket letting out water...

Most of those are doubtful....I would look at it being something I've already suggested or #1 or #2.

Depending on the labor rate at the particular shop less than $150 parts and labor...Inboard/Outboards are usually a bit higher than strictly outboard motors on these repairs, but not that much.

We had a guy bring his boat into the boat shop I've been helping out (I replaced my engine) with a cracked head...He swore my mechanic hadn't changed the impeller out...Well, when we dropped the lower unit, we found the impeller, with my mechanic's initials, and a bunch of sand and grass clogging the impeller...We bagged it, showed it to him and he confessed to running on a sandbar...

Not only did the guy ruin his water pump, and crack the head he also: broke the cooler for the power steering that also sends the water into the engine, and cracked a manifold...Now he ran it for a while (about 5 to 10 minutes from what he said, I can't believe it ran that long) while it was hot (past the 260 mark)...

Now if yours is just running above normal and not truly overheated, then I'd suspect the impeller is beginning to wear down and needs to be replaced...