Overheating issues - 454 Crusaders

[carverjeff]

Hello,
I'm a new member here and at my wits end with an overheating issue. I could use a recommendation for a Crusader gas mechanic or any other input you have.

My 355 Aft Cabin with gas 454 Crusaders runs really well in the slip but overheats at 2800+ RPMs during sea trials. I have replaced/serviced the following:

Impellers (twice)
Heat exchangers (new)
Raw water pumps (rebuilt)
Fresh water pumps (new)
Risers serviced/cleaned
Thermostats (170)
Thru hulls (new) and checked the hull scoops

It runs fine @ 180 degrees until it's under a load and over 2800 RPM's. Does anyone have any ideas, suggestions or recommendations for a mechanic I can consult with. I'm certainly willing to pay a knowledgeable Crusader mechanic as I've had two deals fall through because of overheating.

Thank you!
Jeff

[bud37]

Jeff , couple questions, is there anti freeze or raw water cooled...... is this just one engine or both and when you say fresh water pumps, are you referring to the engine circulating pumps on the front of the engine ?

Sorry can't help with the mechanic in your area.

[Viper]

Welcome aboard.

If your engines have "U" coolers on the front for oil, back flush them. The drain plug on them is also supposed to incorporate an anode. If left to dissolve and break into pieces, the debris will clog the water passages and restrict flow.

Did you inspect the water pump housing for wear? If there is excessive wear, they will not pump enough volume.

Also inspect the insides of the intake hoses, they can collapse and restrict flow.

Make sure the closed cooling system which I think you have based on your "exchanger" comment is purged of all air or she will overheat.

If all you're doing is going by the temp gauges at the helm, you also need to take readings at the engine/s to confirm the temps in case it's an issue with senders, wiring, gauges, etc. Get an IR temp gun and take reading at the engine/s.

Have you ever had a bad overheat in the past, failed impellers, etc.?

[buster53]

You didn’t say anything about hoses. Any chance there may be a partial blockage somewhere? Just a thought, any chance you are over-propped meaning you are putting extra strain on the engines and making them heat up more than they should be?

Is you water strainer clean?

[km1125]

Whenever you changed impellers (recently or even a long time ago) were there ever missing parts? Those can get stuck farther into the system and create blockages.

Also, if it's a freshwater-cooled system, are your manifold part of the freshwater or raw water flow?

[camsaure@aol.com]

km1125, sorry to interject here but I have been trying to contact you on the thread about the norcold fridge short cycling. Thanks, Cam

[km1125]

QR_BBPOST km1125, sorry to interject here but I have been trying to contact you on the thread about the norcold fridge short cycling. Thanks, Cam

Sorry about that. Sent PM

[buster53]

It would be nice to hear from the OP on this.