Boat overheated, melted exhaust bellow, other issues?

[jimmyc607]

First off the motor is a 91 4.3 LX. We took the boat out for the first time last weekend. We cruised around and idled for a couple hours and everything looked to be all good. I'm always cautious the first time out for the season so I made sure everything was in check before I got in the water to do some skiing. I did a few passes around the lake while my buddy drove and then when we came to a stop i could see some smoke coming from the blower vents and my buddy said the temp was around 220ish.

I popped the rear cover and there was a fair amount of smoke that looked to be coming from the carb. We towed the boat into the dock and I just took it home. Upon looking into it a couple days ago I found the exhaust bellow was shot and looks like it melted badly. I've ordered a full new bellow kit and gimble since It's been a couple years anyways but just looking for reasons/ideas about why the boat may have overheated any what else I should look into? I just replaced the water pump in the outdrive last season.

Thanks ahead!

 

[Bt Doctur]

the fan belt popped off. broke off

 

[stonyloam]

Could have picked up some trash (plastic bag) on the water intake. Alpha I right? Your shutters are probably shot. Count on replacing your impeller and entire pump housing, and you will want to check the water pocket cover. Good luck!

 

[skippy2235]

Water pickup to the raw water impeller,
impeller itself.
air leaking into the impeller.
Hose to the engine is broke, damaged, blocked.
plus the above stuff.

 

[jimmyc607]

It is indeed an Alpha 1, The belt is still on and tight so no issue there. I need to pull the outdrive to change the bellows so i'll make sure to grab a new water pump assembly for it. What are the shutters?

 

[skippy2235]

Shutters, funny. I think the real name is flapper valves. Rubber / plastic pieces that stop water from flooding into engine. They are in exhaust system.

 

[stonyloam]

LOL the real name is exhaust shutters, but almost everyone calls them flappers. They are rubber coated steel, and will melt and fail if the exhaust is not cooled by the water exiting the engine. Look for them in the exhaust passage when you pull the outdrive.

 

[trailduster79]

I also have a 91 4.3LX and had the same issue this weekend.

After working out come carb issues I left the dock and the boat quickly overheated with the same results as yours. I towed it back home and tore it apart to find that the impeller had come apart.

So far I have the following damage:

bad impeller
melted impeller housing
melted water pocket
somewhat damaged exhaust elbows
melted exhaust bellows.

I haven't dug further into the back of the engine/exhaust, but I am going to order a new impeller kit with housing and then go ahead and pull the rest of the out drive off to do some more maintenance. I don't think it hurt the motor at all as it will still start with no knocking, but I think mine got a tad hotter than yours did.

I was so concerned with listening to the engine to see if the carb issues were worked out that I didn't catch the overheating quick enough.....

 

[GA_Boater]

I also have a 91 4.3LX and had the same issue this weekend.

After working out come carb issues I left the dock and the boat quickly overheated with the same results as yours. I towed it back home and tore it apart to find that the impeller had come apart.

So far I have the following damage:

bad impeller
melted impeller housing
melted water pocket
somewhat damaged exhaust elbows
melted exhaust bellows.

I haven't dug further into the back of the engine/exhaust, but I am going to order a new impeller kit with housing and then go ahead and pull the rest of the out drive off to do some more maintenance. I don't think it hurt the motor at all as it will still start with no knocking, but I think mine got a tad hotter than yours did.

I was so concerned with listening to the engine to see if the carb issues were worked out that I didn't catch the overheating quick enough.....

trailduster79

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