raw water flow/blockage

I have a 224 merc with an alpha drive. Closed cooling system. Is there any way to tell if there is a blockage by lookng at where the water is coming out of the drive, when on the trailer. Should it be spitting out anywhere in perticular, or doesn't matter?

Re: raw water flow/blockage

its going to come out of the transome ports but unless there is a massive blockage its a tough call on the muffs<br /><br /><br />when and how are you overheating ?<br /><br /><br />tommays

Re: raw water flow/blockage

Best running temp I saw was 175. Hit the sandbar & boiled over. Replaced the impeller, messed with the timing and it ran good till I got on on it, at around 4000 rpm. Then went up to about 200 and I shut her down. Moved the timing, about 8 btdc, got to get it in the water & try it again.

Re: raw water flow/blockage

When you hit the sand bar, you probably injested sand into the engines cooling system. Pull the end caps on the heat exchanger. could be full of sand.<br />When you say "Best running temp I saw was 175" what does that mean??? Was that the highest it got, or is that what you normally run?<br />Not sure why you started messing with the timing, hitting a sand bar doesn't change the timing. If it started overheating when you you hit the sand, then you need to concentrate on the raw water cooling system. Put the timing back to specs so you know what you are looking at.

Re: raw water flow/blockage

I pulled the heat exchanger and it looked brand new. It normally runs at 175. Mechanic at local marina said it should run at 160?? Owner of marina said the 224's traditionally ran warm. Said he even heard of dealers putting resistors in the temp guages?? After hitting the sand bar and overheating I let it cool & headed back to the dock. Have to do a 15 minute no wake trip to get there. On that 15 minute trip it really started running crappy, missing, stalling, etc. (Don't think it had anything to do with overhat, that was the impeller) Figured I had better do a tune up before anything else, to cancel that stuff out. What I am thinking now is that it was the shift interupt switch, I know I kept pulling the throttle back as far as I could because I thought I was going too fast down thru the no wake zone. I shouldn't have messed with it. It runs great once it gets on plane. Trouble now is I can't get the idle down to specs. Lowest I can get it to is about 1100 rpm in the driveway. Haven't got into the water since adjusting the timing last. Gonna float it tomorrow, weather permitting.