Could the exhaust shudder restrict RPMs on my 165?

[luva63]

I recently posted about my plugs burning too clean and remembered that I installed a new exhaust shudder in my 1975 165hp L 6 last winter when I replaced the manifold. There was no shudder at all in my exhaust when I got it. My question is ..could this slightly lower the engine RPMs and top speed? That and the manifold would be the only things that are different from the previous summer. . What do you guys think?

 

[Scott Danforth]

only if the shutter dropped down and is plugging the bottom of the exhaust housing

 

[04fxdwgi]

I was going to leave the exact same response, Scott..

 

[Bondo]

I recently posted about my plugs burning too clean

Ayuh,..... Sounds like a Lean condition to me,....

or water ingestion,....

 

[04fxdwgi]

Looks like the original post changed a bit.

If there were no shutters in there, I would be looking down inside the exhaust and see if they fell off / down into the exhaust pipe. That can cause all kinds of problems with blocking the exhaust. If the S/S rod holding the shutters fell down in there, it can eat a hole in the aluminum pipe below the water line. Very bad..... But blocked exhaust normally causes a rich condition.

Like Bondo says, if the mixture leaned out, that'll cause lower power, but worse, lean condition causing piston / valve damage. Check for vacuum leaks / timing being off too, causing lean condition.

 

[luva63]

Thanks guys. When I did the manifold and shutter, I checked down the exhaust pipe to try to find the old shutter. It was long gone. I'll check my timing. Can I rebuild the fuel pump with a kit to improve the pressure if that turns out to be the problem?

 

[alldodge]

Can I rebuild the fuel pump with a kit to improve the pressure if that turns out to be the problem?

No, need to replace it

 

[Fishermark]

Actually you can still buy a kit to rebuild the fuel pump. It is quicksilver part #49089. It is a fairly easy job. This is for the pump with the filter pointing up.

 

[luva63]

Ok, this is what I found when I did the shutter

 

[luva63]

This is how it looked after I got the new one installed.I had to whittle on it just a little to make it seal and open as it should.

 

[alldodge]

Hope those pam head screws won't cause sealing issues. Would also be a good time to clean and lube your steering

 

[luva63]

I was more worried about the nylock nuts getting hot and backing off, but then realized that the water coming out with the exhaust should keep them cool enough.So far so good.

 

[alldodge]

You do have a point, and they do make lock nuts which do not use a nylon insert. So long as water doesn't stop it should last some time, but unsure as to how long. A rivet would be better I think

 

[luva63]

.I agree,I was going to use rivets but there was no way to get my rivet installer to fit in there to put rivets in . Cooling down here ( NC ) now. Unless it warms back up in time to go see the leaves turn on the lake, I'm done for the season. I'm going to keep an eye on good ole ebay this winter for a new fuel pump to help with my fuel pressure. Thank you for your advice.

 

[alldodge]

Good point, They do make lock nuts which do not use nylon inserts. They use compression, maybe not stainless, another option is to use a regular nut and then use a punch to damage the screw threads. Just a thought, you have some time to think os some others before spring. have a good one