Volvo penta 225d over heating problems

[Rambo420]

Hey guys I’m new to the community. I recently got a boat that has a 225 Volvo penta. Motor runs great. When at low rpm’s runs fine and no over heating issues. When I throttle up it immediately heats up. My first question is what can be causing this issue. I was told it’s likely the impeller. My second question is where is the impeller on the penta located and what kind of impeller do I order? As I said I’m new to all this but I am mechanically inclined and I have chose to maintain and do all repairs on this motor myself so I can learn it in and out, save on labor, and enjoy my boat for years to come.

 

[kenny nunez]

The pump is on the front of the crankshaft. Most times the pump is not the problem but it must be checked first. It is held on with 3 bolts on the crankshaft pulley. Post a side profile of the drive unit as there are 2 other places that can cause an overheat condition.

 

[Rambo420]

I just had it checked out today we have narrowed it down to either the impeller or the left manifold being clogged

 

[captmello]

changing the impeller is a good first move. it should be changed every two years. is this a fresh water or salt water boat? when you day it overheats when throttled up, is it on the water, or in the driveway? these outdrives can develop air leaks that can cause overheating when the boat is on plane but not when sitting off plane.

 

[Rambo420]

changing the impeller is a good first move. it should be changed every two years. is this a fresh water or salt water boat? when you day it overheats when throttled up, is it on the water, or in the driveway? these outdrives can develop air leaks that can cause overheating when the boat is on plane but not when sitting off plane.

When on plane. I just bought the boat but from what I understand it was mainly used fresh water

 

[captmello]

When on plane.

if it were me, I would pull the upper gear box. it will allow you to examine the ujoints, check for play in the drive shaft bearings, and change the ujoint bellows.
while off it allows you easy access to the water fitting just below. those fittings corrode and leak air. you'll need some new orings etc, but it will give you a much better idea of the condition of the outdrive and may solve your overheating.
if you plan to do your own maintenance, which is best imo, this is a good start on a 35+ year old boat. let us know if you need help along the way.