Prop off during test

jimrockireland

Petty Officer 2nd Class
Joined
Jul 8, 2013
Messages
141
I have a 1983 MCM228 with a MC1 sterndrive. I am having trouble circulating water through the sterndrive and the boat engine. I took off the lower stern drive unit to look at the water pump (which was good). Now I am going to put it back together and do some testing with the sterndrive in a barrel of water.to see if I can figure out the water circulation problem. My question is can I leave the prop off when I test run the outdrive in the barrel of water or will not having the prop on affect any of the testing?
 

pckeen

Commander
Joined
Jun 20, 2012
Messages
2,067
The prop will impact the rpms. It'll run much faster, much easier without the prop. You may want to leave it on.
 
Last edited:

Pete104

Lieutenant
Joined
Apr 30, 2011
Messages
1,439
You'll be fine with the prop off for barrel purposes! Make sure you get AV plate under water by a couple of inches. That pump don't suck it pushes!

Pretty vague start to the post BUT you are on the right track. Especially the description of the drive.

Don't know the history or what you're chasing but don't dismiss broken impeller pieces or melted water pocket.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,468
Ayuh,.... Don't use a barrel, use muffs,....

Ya can't get the drive deep enough in a barrel,...
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,093
You really cant tell by looking, best to replace the impeller if atleast 2 years old.
Thats very true, the barrel will more than likely wipe out the impeller
A better way is to remove the drive and use a hose in the water inlet to isolate it in the drive or the motor
 

wahlejim

Master Chief Petty Officer
Joined
Jul 23, 2015
Messages
884
I have that same motor, there are much easier ways to determine where the blockage is occurring. When is the last time you replaced the impeller? If impeller is new, look at the flow diagram for your cooling system.

Lack of water flow is one of two causes: poor supply or blockage

Start with the common failure points: impeller(as others have mentioned, you can't tell just by looking at it, replace it if you don't know when it was done last), water hose that connects the outdrive to the transom, thermostat, engine mounted water pump, exhaust risers, and shutters.
 
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