2006 150 DFI Optimax Overheating Issue

[iwish4fish]

Current dets:
2006 DFI Opti 150, Ser# 1B36xxxxx

Overheats between 2-3k when plowing, no overheat or alarms at extended idle or above 3k when on plane.

New: Thermostats(verified good), water pump, poppet valve, strainer.

Notes:
1. When i pulled the lower unit the copper long water tube comes out making reassembly a pain and has me questioning if it’s properly seated uptop.. Leaking or not seated??
2. I did find some grass in the poppet valve and strainer.. Blocked passage?
3. Motor had 180hrs, I’ve owned and operated it for the past 90 without this issue on same haul.

At a loss- thoughts?

 

[Chris1956]

You may be slightly over propped at "plowing speeds". That would be unusual.... Not many travel at that speed except in a storm.

Alternatively, the poppit valve is supposed to open at about 2000RPM. Maybe the poppit valve is still closed leading to overheat. You did put the correct poppit valve in the motor?

Put a torque wrench on the headbolts and make sure all are tight. A compression leak can cause overheat. i think this is a longshot, however.

I do not know what seal you have in the exhaust extension. My old inline six was a real PIA to get the water tube back in if it fell out. It makes sense for you to lube the end and work it into place, feeling that it is right.

 

[iwish4fish]

Hi and thanks for the response!
Poppet-I believe it is the correct poppet as i matched it to the old one. Additionally, the problem started before i replaced the poppet, therms, etc. so my brain says these probably are not the issue.. but ??

Cooling tube- The tube is NOT tight and will not stay in, making reinstall that much harder. Should i assume it should be tight?

Over-prop- I’ve had this prop and regularly plow out throw the inlet for my passengers comfort for 6+ years and have never had the problem till last month. Now it happens regularly and is repeatable.

Thanks

 

[iwish4fish]

Any other thoughts?
thanks all