pearson 424 w60 overheating

[tinkrman69]

Hello All.

I'm new to this forum, as a member. but have been reading it for a while and am impressed with all the knowelage, imparted here.

I have a pearson 424 with a w60 auxiliary. It started overheating at around 1200 rpms. I noticed the water flow out the exhaust was weak. I acid bathed the heat exchanger and flushed the fresh water side and it helped a little I then was able to get up to 1500 rpm before overheating. I found that the raw water hose on the suction side was collapsing. I replaced that with pipe and hose at each end for vibration and installed a new raw water pump. things got better, but still overheated at 1800 rms I've flushed the whole raw water system, including the through hull, with muriatic acid. it improved the water flow. but am still overheating at close to 2000 Rpms. I'm stumped. there is no smoke out the exhaust, white or balck. I've been looking for a way to bypass the h2o heater but haven't found a diverter valve that will handle the temp load.

Any replays are greatly appreciated.
Lance

[DeepFrz]

Have you removed and inspected the exhaust injection elbow?