still gets hot
- Thread starter memaw777
- Start date
You don't mention a drive so I expect you have a straight I/B , not I/O. And since you replaced manifolds it wouldn't be a full FWC system but could be either full RWC, or possibly 1/2 FWC if it has a heat exch. .
Still sounds likely there may be a RW restriction farther upstream. Oil cooler? RW intake hull scoop strainer or sea water strainer or hose crimp or hose delamination , or....?
You can back flush an oil cooler into a bucket , and inspect hoses and clean fouling and paint layers from hull intake slots or holes.
RW hose suction side could have inner support spring which has corroded away and allows the suction to collapse the hose at higher RW pump demand.
Is timing correct & do spark plugs indicate good combustion, not too lean mix?
Is the engine compartment passive venting still attached and intact?
Still sounds likely there may be a RW restriction farther upstream. Oil cooler? RW intake hull scoop strainer or sea water strainer or hose crimp or hose delamination , or....?
You can back flush an oil cooler into a bucket , and inspect hoses and clean fouling and paint layers from hull intake slots or holes.
RW hose suction side could have inner support spring which has corroded away and allows the suction to collapse the hose at higher RW pump demand.
Is timing correct & do spark plugs indicate good combustion, not too lean mix?
Is the engine compartment passive venting still attached and intact?
What time frame between cool to full throttle and hot. Could be thermostat or the little balls in the housing being sticky from rust or other build-up from rusting housing. There are replacement therm housing that are SS and cheaper than new cast-iron.
sorry it is rwc also IO I watched all the hoses while runing didn't see any collasped it has the spring and balls at the thermostat can you remove these and leave them out i noticed the hoses coming from there were hardly warm at all
Besides getting hot, how does the engine run when 4V kicks open? I think David is sniffing at a possible vacuum leak... Maybe secondaries opening but delivering a very lean fuel mixture. Do your spark plugs look normal, or like they've been hot? If it's lean, it's hot, and there's risk of pre-ignition. I'd sooner believe it's a cooling water issue, but still wanted to ask.
Has the outdrive been off, worked on lately, water pump repair/replace?
Has the outdrive been off, worked on lately, water pump repair/replace?
If the engine is hot at higher loads and those hoses are cool , I'd guess odds are those poppet-type valves are already staying open more than they should and have decent RW flow through them while too little is being allowed to circulate through the engine to dissipate heat except at lower rpms.
That would seem to indicate either the t-stat is not opening enough for normal warm engine flow or part of the t-stat housing is clogged or the circ pump is not doing its job well.
As I understand it , those hose ball and springs are flow pressure activated (opening) when the t-stat is closed , to provide bypass flow to the ex. manifolds and out the riser exhausts.
I would expect normally the ball/springs should only open the engine is cool enough to have closed t-stat and possibly at high speed rpm to handle excess flow from the drive intake and RW pump.
I'd suggest confirming the ball and springs are intact and can close firmly & tightly when RW pressure is not present ,
... then clean the whole t-stat housing ass'ly if it looks like it could use it,
...then put the t-stat in a pot of warming water with a candy thermometer to see if it opens around 140*F and opens fully.
Is the belt tight enough the circ pump pulley and shaft turns OK, ... and no leaks at that pump?
Perhaps confirm all the hoses are connected to the right barbs too.
