Overheat and shutdown

[RedNakedness]

So, last night my '92 Malibu Sunsetter wouldn't start while I was sitting in the middle of the lake with the sun almost behind the trees.  I cranked and cranked until it finally started..  It immediately started heating up and smoking. I was afraid if I killed it I wouldn't get it started again. Retrospectively maybe I should've killed it. But, I had the water bags filled up for surfing so I hooked up the pump to a bag and started hosing down the engine while she crept back into the dock.  Got all the way to the dock before it died.  When I got home I pulled the impeller and of course it was toast and the housing was chewed up something awful.

Seeking advice on what to do now.  I ordered new housing and impeller kit.  What I've done: Flushed the transmission cooler, dumped plastic out of the intake hose and hose running to the trans cooler, cleaned all the pieces of plastics that washed back to the intake housing when I flushed it, drained each manifold by removing the hose at the bottom.  Is there any other hoses I need to take off?  All of them?  Do I need to flush the engine components?  If so, how to do that if the engine is not running? When I put a water hose to the port where water enters the manifold, the water couldn't enter.   Other items to take care of? I was thinking I should change oil and transmission fluid? I was hosing the heck out of the engine when I was motoring in, so water got on everything.  Concerns? I realize the obvious is to replace the chewed up parts and see what happens, but I was thinking I needed to be sure I got all the plastic and rubber out of the system.  Finally, what causes this? The impeller was brand new (3rd time on the water).  My only guess is that somehow the fins on the impeller got damaged when installing (was hard as heck to insert) or I sucked up something that damaged the housing and it all went downhill from there.  Brings up a question; do I need an inline filter/screen to filter water debris before it enters the impeller?  I watched some yt vids and it seems the older boats didn't ship with water filters but newer boats do.  

[wdr]

Crunchy water will cause it. New impeller or not. Its nearly impossible to damage an impeller during replacement unless you are using ice picks to install it.  I know of guys that have never replaced an impeller and know guys that can’t go a season without having an issue.  I have found and been the victim of parts of twist off bottle caps, trash bags, bark, grass you name it. Keep an eye on the trans cooler if you don't have a strainer and you should be fine. The pick up on the outside of the boat  should keep out most of the worst of the crud/

[formulaben]

Agree with above, but there are cases of a defective impeller spinning on its own shaft, but my guess is you sucked something in and it damaged the impeller.  Ever since I installed a strainer on the raw water intake my impellers look brand new when replaced.  After seeing what it filtered it out makes sense why that is so.  Last one before the strainer install had all kinds of cuts and was only 1 year old.

[RedNakedness]

I had just changed the oil and trans fluid.  3rd time out on the water this year.   Is it advisable to change the fluids again since it got so hot? 

[Bozboat]

40 minutes ago, RedNakedness said:

I had just changed the oil and trans fluid.  3rd time out on the water this year.   Is it advisable to change the fluids again since it got so hot? 

Depends on how hot the engine got.    Did it get hot enough to damage the block?   Does the oil smell burnt?  Did the exhaust hoses burn?

[Faceplant409]

Anyone ever fry an impeller by idling too long?

I think I did that Friday. Replaced it on the water Fri night. 

[formulaben]

18 minutes ago, Faceplant409 said:

Anyone ever fry an impeller by idling too long?

On the water?

[Faceplant409]

Yes. 

Put in. Idled 5 min to slip. 

Then let it idle for 10-15 min while I situated dock lines for the weekend. Went to set up camp.  Came back and as soon as I started it it went to limp and beeping  

I had fried a globe impeller with 8 hrs on it  

 

[justgary]

I happen to like the Globe impellers, but a lot of people say they have to rev the engine right after starting it to get the pump to prime.  It sounds like your pump never primed and the impeller ran dry for too long.

Good thing you had a spare with you!

 

[RedNakedness]

Well, an update to my misery...

I replaced the impeller and the housing that had holes in it after the impeller failure.  I hit the lake and it started up just fine but she's running really rough and choppy.  I can't get her to idle successfully.  She lunges and  lurches something awful.  I added a sediment filter in the intake line and the engine stayed nice in cool... just really rough..Any suggestions?  

[Michigan boarder]

42 minutes ago, RedNakedness said:

Well, an update to my misery...

I replaced the impeller and the housing that had holes in it after the impeller failure.  I hit the lake and it started up just fine but she's running really rough and choppy.  I can't get her to idle successfully.  She lunges and  lurches something awful.  I added a sediment filter in the intake line and the engine stayed nice in cool... just really rough..Any suggestions?  

I would do a compression check.

[RedNakedness]

I know this is a dumb question...but can I do a compression test on the trailer with no water?  I watched a YouTube video that says disconnect the fuel and central line that feeds the distributor. My concern is that I don't want the new impeller to spin dry.

[Sixball]

Not a dumb question.  Yes you can do this on the trailer. You are not going to start the boat only turn the engine over. For safety you should pull the coil wire. If you have a lanyard you could pull that. I am thinking you have watched the procedure to do a compression test. If so its not a bad job.  

[mackie12]

I have always done it on the trailer, pull lanyard and you are good to go! It is a very simple task, but be sure you have a good tester, not a princess auto cheapy....

[Michigan boarder]

21 minutes ago, RedNakedness said:

I know this is a dumb question...but can I do a compression test on the trailer with no water?  I watched a YouTube video that says disconnect the fuel and central line that feeds the distributor. My concern is that I don't want the new impeller to spin dry.

It will not hurt the impeller.  You will rotate the crank about 5 or 6 times to test each cylinder, so the impeller will not build up any heat to hurt it, even while dry.  If you are still concerned, you can loosen (or even remove) the belt that turns the impeller so it doesn't spin, easier than removing the impeller and it should be the first belt you have access to, in front of the alternator belt.

[RedNakedness]

Ok.  Here's the update on compression test. I have no idea what this means lol, but I think it means something is bad with a few cylinders. What now experts?

cylinder  - pressure

1 - 125-130

2 - 145~150

3 - 135~140

4 - 85~90

5 - 145~150

6 - 145~150

7 - 145~150

8 - 140~145

 

[JeffK]

Unfortunately, time to start taking things apart.  There are folks on here way better at the engine thing than I am, but I have enough experience to be dangerous.  #4 is definitely an issue.  #1 is something to track.  On a big overheat, you run the risk of a head gasket issue, with a potential warped head.  I've replaced both before, but it isn't a Saturday mechanic style job.  I'd look into finding a good rebuild shop (or buddy with that skillset willing to work for beer and pizza) around you and speak with them.  Where do you live?

[justgary]

Maybe try a leakdown test before you take it apart.  Or at least repeat the test with a little oil in the cylinder. 

From your description, it's probably just a head gasket, and the results of the compression test won't change with oil.  If so, not too difficult to fix. 

BTW, you can always pull the impeller or just remove the front plate and squirt some water on it if you are worried about it. 

[RedNakedness]

If it was the head gasket I would think there would be water in the oil, no?  I drained the oil and replaced the oil filter and the oil looked fine. Not milky.  I'll have to ytube a leakdown test. 

[Sixball]

27 minutes ago, justgary said:

Maybe try a leakdown test before you take it apart.  Or at least repeat the test with a little oil in the cylinder. 

From your description, it's probably just a head gasket, and the results of the compression test won't change with oil.  If so, not too difficult to fix. 

BTW, you can always pull the impeller or just remove the front plate and squirt some water on it if you are worried about it. 

A leakdown test give much more info on issues. It will let you know Head gasket, valve, rings so much more and can sometimes see things you could miss on a tare down and repair what is easy to see. You could check with a dealer service or a good speed shop or if you know someone who runs a race vehicle. It will be something I think you will need some help with.

[Sixball]

Did you run #4 more then once!  If not that is the first thing I would do is rerun #4 to be sure all was well with the test run.  It should be repeating. 

[RedNakedness]

Question about the compression test... should I remove all the plugs at once and test or does it matter?  Since running the test last week, I've been doing a lot of reading and YouTubing. Some videos I watched said to remove all the plugs and test, others were not specific. 

[ORMailbuboater]

Other things to do - Parts of the impeller can also foul the thermostat.  You may want to pull the thermostat housing to be sure that is clear and functioning properly.  Other wise could heat up again if stuck closed.

Can't help you with the compression issue.  Hopefully as others said only a head gasket.  Good luck.