Questions

[hummingbirdbassist]

On the hard making last minute adjustments so here goes
Yanmar 2qm15 runs, idles well, revs well, slows down well, .had a rusted out downdraft mixing elbow, replaced with riser type elbow. Started engine let it run about a minute, put impeller hose is bucket of water , ran idle up and only had mist or trickle of water out exhaust.( sorry Mrs Scrutchins, my high school English teacher for the run on sentence) lol
Is this trickle normal or shall I look for some sort of blockage?
Check all hoses leading to riser, clean, thermostat looks good.
Does thermostat open up at certain temp to allow more flow?
Replace water impeller ?
Any suggestions?

 

[woodster]

On the hard making last minute adjustments so here goes

Does thermostat open up at certain temp to allow more flow?

Any suggestions?

yes it does usually 150 degrees you have to get it up to operating temp to have full flow

 

[kloudie1]

Did ya put a bunch of lube on the impeller before closing it up? If not, ya may have damaged the impeller during the minute dry run? Should have more than a trickle. The engine cooling circuit has a cool water bypass which routes the raw water coolant around the block and out, so flow out back is about the same with thermostat open or closed .. Thermostat starts to open at about 100F, fully open at about 125F .. Look for air leaks in the impeller cover or hose connections or sea water strainer. If bypassing strainer, look carefully at the hose and connection at the pump.. it only takes a very small air leak to overcome the pump. Try putting the bucket above the pump level. did you change the in-block zincs? We have found a lot of fouling and restriction around the zincs in a 2QM.. We were able to knock it clear and get good flow after cleanup in the passages around the zincs.

 

[hummingbirdbassist]

Kloudie,
Do you have a email or number I can call to talk about this engine?
Hummingbirdbassist@gmail.com is mine . Please be in touch
Will