Impeller , water circulator, something else?

[jmatteo1]

I'm in the process of getting a '78 Wellcraft with a Mercruiser 898 in it going after 2 years of storage (see Clicking not starting) Anyway I got it started with muffs on but she wasn't spitting out any water. recehcked the oil and plugs, no water there. Took off the lower unit. The impeller was slightly damaged, so I replaced it, same results, no water coming out. I checked the intake for a blockage and found nothing. Am I correct in thinking that the impeller should be taking in water at an idle with the muffs on? Also, I took off a hose from the port side of the thermostat housing and ran water in slowly. It came out of the exhaust as it should, and it also circulated back around and came out of the thermostat housing where I took off the hose. Any suggestions would be greatly appreciated.

 

[Don S]

Re: Impeller , water circulator, something else?

Yes it should pump water at idle, pull the hose off inside the boat and with the water on start the engine and let it run for 5 or 10 seconds and see if you get any water on the inside. If you do, you may have plugged risers that won't allow water to flow past them and if they are plugged, the water won't flow.

 

[jmatteo1]

Re: Impeller , water circulator, something else?

Do you mean the hose that comes into the boat from the outdrive, Don? What is it connected to?I was thinking about a blockage, when I ran a garden hose through the upper hose. Since it came out of the exhaust through the outdrive, I figured it wasn't blocked. Secondly, how would one go about cleaning the risers if they are blocked?

 

[Don S]

Re: Impeller , water circulator, something else?

I don't know if you have raw water cooling or closed cooling, so just follow the hose from the transom shield to where it enters the engine.<br />If you have water there, pull a hose off going to the exhaust and see if you have water there. If the manifolds and risers are plugged up, then they need to be replaced, not just cleaned out.<br />It's the rust from the inside of the manifolds and risers that flakes off and plugs the passages and if those webs end up with a hole in them you will have water in your cylinders and it can cost you an engine.