Steam coming out of exhaust!!

[nicksquid]

Started my boat 1988 mecruiser 5.0l for the first time this year(on the muffs). I ran it for about 5 min and then it started to blow white smoke out of the prop exhaust. It is def. steam from water. The boat heated up to about 200 degrees and stayed there. where do i start looking for trouble

 

[Don S]

Re: Steam coming out of exhaust!!

The raw water pump impeller is the first place to look. The impellers on the Alpha I's, MR's and R's were only good for 2 years max.<br />How old are yours?

 

[nicksquid]

Re: Steam coming out of exhaust!!

heck......i don't know? i bought it from a friend who only had it a year. i am putting a new lower unit on tommorow so i will probably be right there close to the impeller huh? but, would this cause the white steam to come out of the exhaust?

 

[bugstruck]

Re: Steam coming out of exhaust!!

I have the same white smoke on my 470 mercruiser. I also have water entering the back cylinder. I'm going after the exhaust riser first unless someone steers me to a better start point. Running a compresssion test first though.

 

[nicksquid]

Re: Steam coming out of exhaust!!

how do you know your getting water in the back cyl.?

 

[Don S]

Re: Steam coming out of exhaust!!

Pull the plugs and look for water on the plugs or rust. When a plug that has been in the engine for a while and looks perfectly clean, like new, that indicates it has been steam cleaned due to water in the cylinder.<br />But don't expect the worst yet, old impellers are the biggest overheat problem known to boaters.

 

[nicksquid]

Re: Steam coming out of exhaust!!

ahhh.....ok<br />would a bad impeller make steam come out of the exhaust too?

 

[Don S]

Re: Steam coming out of exhaust!!

Sure, if you only have a little bit of water in very hot exhaust gasses, what do you expect to happen. That is why you need a large flow of water going through the exhaust.... It doesn't all go through the engine on a raw water cooled engine.

 

[crazyray]

Re: Steam coming out of exhaust!!

bugstruck I get water in my 120 hp if I stop real quick like if key is turned off. has only happened twice in 4 yrs once I did it 2nd time grandson turned key off, both times motor was hydrolocked had to remove plug to get to turn over, think there is an flapper check valve in exhaust that has gone bad

 

[nicksquid]

Re: Steam coming out of exhaust!!

ahhh....thanx for the help. where is the best place to order the kit from?

 

[Don S]

Re: Steam coming out of exhaust!!

What "Kit" are you wanting to order???

 

[nicksquid]

Re: Steam coming out of exhaust!!

the impeller kit

 

[KaGee]

Re: Steam coming out of exhaust!!

Try Iboats!

 

[nicksquid]

Re: Steam coming out of exhaust!!

removed lower unit to find a broken impeller!!!! hopefullly that is all it is.......

 

[Bondo]

Re: Steam coming out of exhaust!!

Back Flush the Cooling system,... From the T-Stat Housing back to the Impeller,.....<br />Make Absolutely Sure that you find ALL of the Missing Pieces of the Impeller.........

 

[nicksquid]

Re: Steam coming out of exhaust!!

just fill the thermostat housing with water until the pieces all come out?

 

[bugstruck]

Re: Steam coming out of exhaust!!

Nick13, I need to replace the impeller anyhow so I may go for that first but that rust on the plugs and water in the back cylinder isn't a flapper issue on mine. It's been laid up for 3 years. I replaced my flapper 18 years ago and my mechanic later advised removing it on my boat the next time I had problems with it. I suspect just the frame is left now. It gave up in year 5 initially so it can't be much there now although I'll check that too but just for restriction purposes. My riser sits high enough I'm not very prone to backwash coming in the exhaust in any stopping or sea condition. Many boats are vulnerable to that though. The smoke I'm seeing could be impeller or riser but the water is riser I suspect. Replaced that about 14 years ago when it was 10 years old so I know the current one's toast. Problem I have is so many home projects it's hard to get on the boat and stay with it. Eventually though, even if it's end of summer. I'm going to splash it next year or bust.

 

[nicksquid]

Re: Steam coming out of exhaust!!

well i replaced the impeller and now the boat works great!!!!! Now all i need is a few decent women in bikinis to hop onboard.....lol