95 Mariner Magnum 40hp 4 cyl. overheating

Hello, I've got a 95 Mariner Magnum 40hp that overheats within 5 minutes. I have replaced the oil warning module and the oil pressure switch and the oil tank is full. That being said the alarm does stop when I disconnect the module. But, when I start the motor the water coming out of the tell-tale is immediatly warm, long before the motor is. After about two minutes the water is too hot to touch and then the alarm comes on a couple of minutes later. I have learned that this motor has no thermostats and regulates temperature through restrictions in the exhaust plate and other areas. My question is, is there a way to clean these areas out? I shredded an impeller a few months ago and am wondering if small pieces of impeller might be obstructing the water flow. Also, does this motor have a poppet valve, or some other way to discard water overflow? As always, any help is appreciated. Kyle

Re: 95 Mariner Magnum 40hp 4 cyl. overheating

Small bits of the old impeller often clog water passages and cause over heating.

You may have to remove the exhaust side cover and the cyl cover to clear passages.

Re: 95 Mariner Magnum 40hp 4 cyl. overheating

Thanks for the response. I took both plates off and I'm gonna blow air through all the passages, I don't see anything clogging the passages though. I'll let you know how it goes. Thanks Kyle