Engine Oil

misslynnie

Recruit
Joined
Jun 17, 2011
Messages
5
1998 - Mercruiser 350 - V8 - 5.7L I/O

Having a problem with engine oil and lower part of motor overheating. I have cleaned both risers (not bad) and manifolds. Port manifold replaced, starboard cleaned (very good flow). Oil pressure maintains 40-50 psi. Motor and oil both cool when rpm's are lowered from 3000 to 1000 rpm's. Temperature was measured with I/F gun. Checked water flow at all hoses leading to and from thermostat housing (OK). Thermostat was replaced along with water pump before overheating.

What should be checked and or tested at this point.

Miss Lynnie II
 

mkast

Lieutenant Commander
Joined
Nov 6, 2002
Messages
1,934
Re: Engine Oil

Just curious, what temperature reading are you getting?
 

Pulse8

Cadet
Joined
May 31, 2011
Messages
13
Re: Engine Oil

check if your Y exhaust isn't blocked by a old pair of exhaust flappers which could be broken and fallen into the Y exhaust and blocking your exhaust way.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Engine Oil

Having a problem with engine oil and lower part of motor overheating.
What do you mean by lower part of the engine? The oil pan?

Does the engine temp gauge on the dash indicate an overheat or do you have an alarm going off?

Temperature was measured with I/F gun.
What was you aiming at when you measured the overheat?

Thermostat was replaced along with water pump before overheating.
Does that mean that everything was OK prior to replacing the pump and thermostat? and which pump are you referring to? Raw water pump or the circulation pump?

Checked water flow at all hoses leading to and from thermostat housing (OK)
What did you compare that to in order to determine an acceptable amount?
 

dingdongs

Chief Petty Officer
Joined
May 29, 2009
Messages
649
Re: Engine Oil

did you change the impellor in the drive as you cannot be getting flow through the engine.do not run again until you replace impellor as engine will not survive 4 long.have you run the engine ever without water muffs being connected to the outdrive.if the answer is yes then the impellor is toast.
 

misslynnie

Recruit
Joined
Jun 17, 2011
Messages
5
Re: Engine Oil

Never ever started engine w/out muffs and drive impeller has not been changed.
 

dingdongs

Chief Petty Officer
Joined
May 29, 2009
Messages
649
Re: Engine Oil

would check impellor to confirm its all there and replace in any case.as a quick check you maybe able to undo hose clamp on hose that comes from drive to your thermostat housing.turn water to muffs on and see if you have a good flow.maybe long enough to put in a bucket.a 30 second run will not do the engine any harm.had you ever sucked mud up recently into your drive as you may have a blockage.
 
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