1992 Celebrity, AlphaOned 350 overheating

[SHINTON]

Ok, first of all, I am an accountant by trade so you may have to use small words and speak slowly here!!

I have turned a wrench or two in my life, handling almost anything outside of an engine (rebuilt axles on Jeeps, install lockers in diffs, even replaced stuff on the outside of motor) so not 100% newb but not an engine/carb guy.

With that in mind, paid a local Marina last year to rebuild my carbs...and $1071 later they fixed all sorts of other stuff too and I they put in a impeller kit and a $150 charge for water pump service and various other things.

So, Saturday, got to the lake, backed in, engine fires right up, I let it run at 2500+ rpm for 5 minutes or so maybe while I screw around with other stuff, letting it good warm up and stuff.

Back off, towards idle, and it shuts off. No big deal (took a couple attempts to start it the first time and keep running, typical carb)

But now it will not start, doesn't act like it wants too, battery getting weak...kept trying for 10 minutes or so thinking it was flooded, sigh. Pull it out, went home, charged the battery AND bought a new one, hooked it up to the new one, cranked right up at home shut off.

Sunday...cranks like a beauty, ran it for less than five minutes warming up, backed off slower this time, gets to idle and running good, yeah!!

Backed out onto the lake, we are moving... started driving, everything looks good, but does seem to be running warm, gauge says 220+230ish? I am running 2000 rpm maybe, watch this closely, maybe creeps up to the solid 230+ No idea if the temp is supposed to be a 210 thermostat but I am guessing not.

Start smelling oil stuff, ran around for 5-10 minutes at most...came back into the dock. Backed off the throttle considerably (I had done this once or twice but never below say 1000 rpm) and the smell is getting worse, engine stalls.

I pulled the engine cover, engine is def hot (gauge is closer to 240 now) and the smell is basically the oil on the outside of the engine is burning off from various places.

I am 30 yards from dock, tried to start for the heck of it and acting funny (like Saturday) and not wanting to crank but no big deal I had it drifting where I wanted to go anyways. Drift up, load it up go home.

Tried cranking it when I get home (30 minutes or so) still acting like it does not want to start... come back an hour+ later and it DOES crank up and run for 10-15 seconds and I shut it down. So I know the engine is not locked up...good!

Checked oil, maybe 1/2 quart low if that...looks fine.

So... here we are now.

First of all... I have a few questions I am hoping you can help me with.

I hooked up the ear muffs to the house and started the engine say a month or so ago. I remember seeing the temp gauge being higher than I would want, but that is all I remember.

Question #1. When I hook up the muffs, water seems to "also" shoot out of the sides on the muffs to the sides, I try to get the best fit I can. When the water is on those... should it ultimately run back out of the prop without the engine actually on?

Question #2 If the answer is no... where do I start testing here. I assume I start with hooking up the water and turning it on.. is there a hose on the motor I can unhook to confirm water is coming in/past the impeller? Must the engine be running? (it gets warm / overheats so I assume I have to check these things quickly)

Question #3 Should I run a hose into the input on the water pump instead skipping impeller process.

Basically... what are the steps to diagnose this from start to end. I can handle the process, just not sure where to start.

Finally...is there a good step by step guide out there in a book or such for me to use and not bother you? (Such as how to open and check that impeller? If I do so that would require me buying and replacing such and such seal so...?)

 

[alldodge]

Since you have a carb you should have a 140 degree thermostat and anything above 160 is to much. If you ever ran the motor without being on muffs or in the water, even for a short period, you need to replace the impeller again. At 220 to 240 degrees you overheated the engine and may have blown a head gasket or more. With temps this high you also need to replace all the exhaust hoses and have the exhaust flappers checked or replaced. Also since it overheated you do need to replace the impeller.

Q1: Water will spray out around the muffs and this is normal without the engine running. Water should not be coming out of the prop with the engine off. Never run an engine above 1500 RPM on muffs and try not to do it above that when sitting in the water for long periods.

Q2: Your impeller is shot so it needs replaced. Don't know if it was caused by incorrect installation or by something else you may have done.

Q3: No, never run the engine without water going to the impeller, it will burn it up in seconds.

Pull the plugs and run a compression test to see if your engine is intact. Pull the drive off and replace the impeller. You can find many of the how to's in the top of this section in the DonS adults only

Lets us know what you find or if you have any other questions
Good luck

 

[Bt Doctur]

~~Q1: Water will spray out around the muffs and this is normal without the engine running. Water should not be coming out of the prop with the engine off. Never run an engine above 1500 RPM on muffs and try not to do it above that when sitting in the water for long periods.
I`d like to add what your seeing is called "splash" with the motor off. With muffs providing a reasonable seal ,the instant the motor starts ,the splash should almost completely disappear depending on the water hose pressure and flow. This tell you the impeller is still in good shape.

~~Q2: Your impeller is shot so it needs replaced. Don't know if it was caused by incorrect installation or by something else you may have done
I would add do the splash test first, if it dosent disappear, the pump is not working and drive needs to be removed for repair

~~Q3: No, never run the engine without water going to the impeller, it will burn it up in seconds.
I`d add, it`s sooner that you can imagine..Rermove the drive , get a washing machine hose, cut in half, insert into water inlet hole. This will allow you to run the motor at whatever rpm you choose .

This should be for your drive http://www.boatfix.com/merc/Servmanl/6/6covr3.pdf. When it opens ,click on the box, to access the sections, move cursor all the way to the left , and click on the subsection and number you want, Do not try on the right side.

 

[Bondo]

gauge says 220+230ish? I am running 2000 rpm maybe, watch this closely, maybe creeps up to the solid 230+ No idea if the temp is supposed to be a 210 thermostat but I am guessing not

.Ayuh,..... Welcome Aboard,..... Water boils to steam at 212°,....... A compression test is a Good place to start,....

 

[SHINTON]

Ok, regarding 1 & 2 there and the splash test... I am looking at the diagram for my engine / MCM 350 CID / 5.7L Alpha and I see where the water is coming into the system (assumably after being pumped up from the impeller area/water pump)

If I removed the hose where it goes into the unit above the water pump, if the impeller is working I should see water come gushing out of this pipe? (It appears to go straight through that box and then down into the water pump.

Before I even do that...If I start removing and "draining" those various hoses as mentioned in the diagram, shouldn't they be full of lake water? If they have water in them, wouldn't that mean the impeller is working?

Basically just trying to think through this step by step, if water is getting TO the water pump from impeller area, then the issue is likely either the water pump OR clogged stuff afterwards...?

Beyond the splash...how quickly should I see a return of water coming back out of my propeller ? I would think the volume coming back out of this system should be comparable to the rate of water going into the system...

Final thought or question. HUGE thanks for the links to the PDFS. How "hard" is the process to drop the housing so I can visually inspect the impeller? It looks like it is oil filled so at the very least I will end up having to dispose of some oil, find a replacement oil afterwards? Are the seals destroyed in this process and will need replaced normally?

 

[eng208]

How odd! I have a 1993 Celebrity with a 5.7 Magnum that the exact same thing happened to. It belongs to a friend of mine and I posted about it, yet I got very few responses. I found the exhaust flappers burnt, impeller completely shot (had spun off the hub and was just lying loose in the housing), grooves in the impeller housing, water circulation pump squealing and weep hole had evidence of severe leakage, and the water pick up tube and coupling melted. I found the missing flapper in the exhaust bellows and the flapper pivot pin lying next to the impeller housing. Compression on this one is 182-195 across all cylinders, so I hope the head gasket was spared. The exhaust hoses look ok for now.
Good luck. The engine should run quite cool with lake water and never get over 200 under any circumstances. If it does, something is wrong.

 

[Bondo]

Ok, regarding 1 & 2 there and the splash test... I am looking at the diagram for my engine / MCM 350 CID / 5.7L Alpha and I see where the water is coming into the system (assumably after being pumped up from the impeller area/water pump)

If I removed the hose where it goes into the unit above the water pump, if the impeller is working I should see water come gushing out of this pipe? (It appears to go straight through that box and then down into the water pump.

Before I even do that...If I start removing and "draining" those various hoses as mentioned in the diagram, shouldn't they be full of lake water? If they have water in them, wouldn't that mean the impeller is working?

Basically just trying to think through this step by step, if water is getting TO the water pump from impeller area, then the issue is likely either the water pump OR clogged stuff afterwards...?

Beyond the splash...how quickly should I see a return of water coming back out of my propeller ? I would think the volume coming back out of this system should be comparable to the rate of water going into the system...

Final thought or question. HUGE thanks for the links to the PDFS. How "hard" is the process to drop the housing so I can visually inspect the impeller? It looks like it is oil filled so at the very least I will end up having to dispose of some oil, find a replacement oil afterwards? Are the seals destroyed in this process and will need replaced normally?

Ayuh,..... Welcome Aboard,...... The Impeller, is Always, the very 1st place to look, in Any Overheat situation,.......
When replacin' the Impeller, or the entire Pump housin', m,ake sure ya find ALL the missin' pieces from the impeller,......
If ya miss Any, they'll come back to haunt ya, Bad,....