# Boat runs fine....just not in water



## dcdon

OK. Quick facts. My engine overheated, but not bad damage has been seen. Replaced impeller with housing. 

Motor runs great on ear muffs. Idles nicely, goes into gear fine. A nice stream of water coming out the tailtell hole. 

but once I drop it in the water and it starts sucking water up the impeller it won't idle. And it won't go into gear since it doesn't stay running at idle. I can give it throttle and crank it and keep it running at about 1200+ rpms, but below that it dies out. The whole time there is a nice stream of water coming out. 

it seems to me like the impeller is putting too much of a load on the engine when it is fully under-water or something like that. 

Has anyone ever heard of this happening? 



* I will add that I narrowed it down to the impeller area by having it on the trailer in water then cranking with the engine tilted up out of the water. Idled nicely. Then lowered it into the water and once the water pickup on the foot got under water the motor sounded like it was starting to lag and then went dead.


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## oxbeast1210

I've had that happen before when the idle speed was set to low .
it would run fine on muffs but as soon as it was in the water it would have trouble idling and would due. After my mechanic adjusted it never saw the issue again. Might be worth looking into . What rpm are u idling at out if water? And what us it when in the water?


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## oxbeast1210

When the motor is in the water the prop has to push water, which makes the load greater then it is when on muffs .


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## kanaka

dcdon said:


> OK. Quick facts. My engine overheated, but not bad damage has been seen. Replaced impeller with housing.
> 
> Motor runs great on ear muffs. Idles nicely, goes into gear fine. A nice stream of water coming out the tailtell hole.
> 
> but once I drop it in the water and it starts sucking water up the impeller it won't idle. And it won't go into gear since it doesn't stay running at idle. I can give it throttle and crank it and keep it running at about 1200+ rpms, but below that it dies out. The whole time there is a nice stream of water coming out.
> 
> it seems to me like the impeller is putting too much of a load on the engine when it is fully under-water or something like that.
> 
> Has anyone ever heard of this happening?
> 
> 
> 
> * I will add that I narrowed it down to the impeller area by having it on the trailer in water then cranking with the engine tilted up out of the water. Idled nicely. Then lowered it into the water and once the water pickup on the foot got under water the motor sounded like it was starting to lag and then went dead.


If I'm reading this right, after you changed the impeller/housing you ran it without water going thru it???? IMHO you just burnt the vanes on your new impeller.......
Have you done a compression check yet?? You might have snagged a ring when it overheated. You are putting a slight load on the motor with the prop exhaust in the water BEFORE you even get it in gear. Kinda like the ole potato in the tailpipe trick.


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## Sequoiha

It would help greatly if we knew which motor we were talking about...


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## dcdon

85 Evinrude 150. Sorry for forgetting that part.

The overheat happened before I installed a new impeller. I left it running on muffs for way too long like an idiot and my overheat alarm wasn't working.

The only idle adjustment that i know if is the wheel adjustment thing on the throttle controls where it connects to the motor. I adjusted that all the way to the end that caused it run higher RPMs at idle. I believe its idleing about 800 rpms on the muffs now. Once I drop it in the water it doesn't idle for long enough for me to read the RPMs. It just seems like its straining under the load of the impeller. 

thanks for all the great help.


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## capt'n slim

not sure about that motor but on mine i have to loosen up several nuts and bolts to properly adjust the idle. If ur gonna work on it urself, Get a book on the motor, start checking compression, starting components. weak stator or coil pack can cause the same issue u describe, checl for exhaust leaks when in the water pull the top off the motor and watch for smoke in the engine. The old runs fine on the ears but not in the water is a common issue with about 5000 possible solutions


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## Sequoiha

I think that engine should idle out of the water about 1100 rpms. this is adjusted with the timing which is probably why it is dying when put in the water. it is idling to low and the timing is not correct.


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## dcdon

Thanks kenny and capt. you guys gave me some things to look into.


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## oxbeast1210

ANy luck with the issue?


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## dcdon

We have switched to another boat for the fishing trip this weekend. 

I plan on fighting this motor and timing issue like sequoia said when I get back. I will have to figure out how to do that, but thats what the internet and these great forums are for.


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## Sequoiha

When you get back, come in and sit down with me and i will try to explain how to you..


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