Replacing Burnt Shutter Valve - Trying to Find Pieces

[whitefish1]

Hi guys - I'm replacing a burnt shutter valve on my '93 3.0l Mercruiser. The shutter valve is totally gone except for the pin and some rubber around it. The pieces are likely down the lower pipe. My question are:

How far can these pieces migrate? Can they get into the lower drive unit?
How do I get the pieces out? Shop vac? Should I take the exhaust bellow off?

BTW, I suspected a bad shutter valve because most of my exhaust was coming out of the idle ports instead of the prop.

Thanks in advance.

 

[Don S]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

Yes, they can get into the drive. Pull the drive and look in that area, in the bellows, and pull the prop and look into the lower cavity of the lower unit.

BTW, I suspected a bad shutter valve because most of my exhaust was coming out of the idle ports instead of the prop.

On muffs, that is very normal.

 

[whitefish1]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

Thanks Don - I had the lower drive unit off last year to replace the impellar and I can't remember what was down the water/exhaust passage. I'm sure I would have cleaned anything out if there was. I'll take the exhaust bellows off, but I'm going to try the shop vac first to see what I can pull out.

On muffs, that is very normal.

That's what I've read. But, the exhaust is pretty loud when I'm on the water. Most of the exhaust seems to be coming out of the idle ports at speed.

 

[Don S]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

Then pull it apart and look. Could be nothing more than a bad bellows.

 

[whitefish1]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

Ok will do - thanks

 

[TilliamWe]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

And don't be surprised if the rubber pieces of the shutter are completely gone. It melted to fall off the pin, it may have melted into to small enough pieces to have gone out the exhuast sytem completely.

 

[whitefish1]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

And don't be surprised if the rubber pieces of the shutter are completely gone. It melted to fall off the pin, it may have melted into to small enough pieces to have gone out the exhuast sytem completely.

Good point. I'm hoping to find pieces (something to explains the diversion of exhaust through the idle ports).

 

[ktbarrentine]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

You dont really need to remove the exhaust bellows (unnecessary work)...just pull the drive and look up the bellows into the pipe with a good flashlight. Typically You'll see the pieces at the bottom elbow where it bolts to the transom mount. if not there, then you might see them inside the drive itself (small mirrors help).

 

[fat fanny]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

Pull the elbo off and blow air back through the ports at the prop and they may possibly show up in the bottom of exaust tube mine did and I grabbed them with a flexable grabber tool you may even get lucky and see them at the bottom of the exauhst tube.

 

[whitefish1]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

Ok, I tried connecting my shop vac to the lower exhaust tube and plugged off the idle ports and exhaust ports at the prop (took the prop off). I good some good suction going. Lots of air moving thru the prop exhaust port as I could hear and feel lots of suction when I removed the rag. Nothing came out except some black dust. I even tried using a wire and to feel around the bottom of the lower exhaust tube. Nothing. Then I tried using a small vac hose that reached the bottom of the lower exhaust tube. Still nothing.

Probably nothing there, but I'll pull the drive and look at the bellows when I change my shift cable.

BTW, I haven't had any problems with water flow or over heating. Lots of water comes out of the idle ports and some water comes out of the prop when on the muffs.

fat fanny, if I did get something at the bottom of the lower exhaust tube, how would you see it? Did you just feel around with a wire?

 

[Oshkosh1]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

If it's any consolation...I have the same issue. I searched for missing pieces and found nothing. I have good water flow through the relief ports/little through the prop on the muffs or underway. No overheating/performance issues either, resigned to saying "that's how it is" with this boat.

 

[stonyloam]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

If you pull the outdrive and look in the exhaust chamber and they are not there, they are probably long gone, removed when the po had the outdrive off.

 

[whitefish1]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

Oshkosh1 - I may be in the same boat (pardon the pun). Sucks though. I guess I have to get a bigger stereo. What type of boat were you running the i/o on?

If you pull the outdrive and look in the exhaust chamber and they are not there, they are probably long gone, removed when the po had the outdrive off.

I had the drive off last year and I can't recall if there was debris in the exhaust chamber or not. I think I remember finding bits of something and wondering what the heck it was.

 

[Oshkosh1]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

Oshkosh1 - I may be in the same boat (pardon the pun). Sucks though. I guess I have to get a bigger stereo. What type of boat were you running the i/o on?

A 19' Wellcraft. Mercruiser 250/I6 Alpha1. I looked and looked...even bought a flex cam. Found nothing.

 

[stonyloam]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

The remains of the shutters would be substantial pieces of steel, "D" shaped, 1/2 the width of the exhaust pipe, would be difficult to miss.

 

[whitefish1]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

The remains of the shutters would be substantial pieces of steel, "D" shaped, 1/2 the width of the exhaust pipe, would be difficult to miss.

Hmm...replacement looks like its plastic or hard rubber. Don't see any steel.

 

[Eric 3.7LX Alpha 1]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

The rubber is an outer coating except where the halves join in the middle of coarse, there it's only rubber so it flexes.

 

[1979 Quartermasters]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

The old ones are steel of some kind



The new ones are up-graded to a hard rubber of some kind.....

Ken

 

[whitefish1]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

Your guys are right. After I posted last night, I tried to think back as to what I had found at the bottom of the lower unit. I went back in to the old parts boxes and this is what I pulled out; one of the metal inserts for the shutter. At the time, I had no idea what this was.



So at least I know I found one half. The question is where is the other half. Is it possible for one of these pieces to make it past the prop exhaust ports? I'm guessing not. If not, then the other piece still has to be between the lower exhaust tube and the lower unit.

 

[Oshkosh1]

Re: Replacing Burnt Shutter Valve - Trying to Find Pieces

The new ones are up-graded to a hard rubber of some kind.....

Yes...the only metal is the center span. The two split "flappers" are all rubber.