4.3 v6 mercruiser overheating

[kmiller148]

I recently became the owner of a 1986 Larson Citation DC-190.(First boat) The boat sat without being ran for about 10 years before I got it. It has a 4.3 V6 mercruiser inboard.

I changed the oil, drained the fuel and put in a new battery. The engine started up and sounds great!
I have only run it on muffs - after a few minutes it starts to run hot.
I have little knowledge of boats, but from searching it sound like I need to replace the impeller and thermostat.
Does this sound like a good place to start - anything else I should look for? Also if someone can point me in the right direction on where to order those parts or the correct parts numbers would be great! Thanks!!

 

[alldodge]

Howdy
Having an Alpha drive, I would drain the lube from the drive
Separate the lower from the upper half of the drive and remove the water pump and impeller
Inspect housing to determine if more then just the impeller and gasket is needed, maybe pump housing

Inspect gimbal bearing

This is full bellows kit with bearing
https://www.ebay.com/itm/Transom-Rep...ox!42717!US!-1

This is complete water pump kit
https://www.ebay.com/i/323984087252?...MaAsySEALw_wcB

May also need lower shift cable and trim senders

 

[karayj]

Impellers rot and fall apart after sitting for a while. when you run the boat for while it looks ok and but then after using it a 2nd or 3rd time it will fail. Happened to me, when I went to replace it , it was garbage. Did you smell burning rubber or bits of rubber on the ground? Any boat sitting for a year BY DEFAULT CHANGE THE IMPELLAR... I was I was told the same . Live and learn, the coast is too cheep and the job too easy not to change it every 2 years.

 

[Bondo]

but from searching it sound like I need to replace the impeller
- anything else I should look for?

Ayuh,........ Welcome Aboard,....... Make sure ya find All of the broken bits of the old impeller, or they'll cause problems later,......

Back-flush the line, from the t-stat housin', with the lower unit off, if necessary,......

 

[poconojoe]

Be careful, you dont want to overheat these engines. You can damage the exhaust shutters for one thing.
Definitely replace the impeller. The rubber is probably dry rotted. As stated, by running it, you may have sent rubber parts of the impeller throughout the system. You will confirm or deny this when you see the condition of the existing one. You will also become familiar with and be able to inspect the stern drive when doing the impeller replacement.