TOPIC: Manifold troubles on a 165 inline merc

I pulled the manifold this evening and much to my sorrow, I poured water out of the exhaust port of the manifold when I removed it. Found three cracks with rust around them looking inside the ports. And to top it all off. it was as I suspected on the shutter/flapper. So now I'm on the look out for a manifold. Glad now I have a little while before spring. Anybody know of a source for one of these manifolds?

Search Fredwarner1 at ebay. He's got probably what you need. If not seen, ask him. Nice guy, great prices, fast ship too. Its where I got manifolds for my (sold) 77 350.

I got a Barr Marine manifold from Go2Marine. www.go2marine.com/ It was 478.52 in 2013. I also bought a Riser, the end plates and every thing else I need to replace the cooling.
part number for the manifold was MC-1-58759
front end cap part # 1-60252
rear end cap part 1-73813
Riser was MC-20-76351 (on the invoice it says 710-76351A04)

I also got the gaskets, bolts etc from them.

By the way, i tried to replace the flapper valve and it was a disaster. I talked to a Mercury Marine technician and he said "leave it out. It's not necessary" Well.... maybe on my boat. It runs fine and I don't get any water being sucked in, but that might not be right on yours. It is a bitch to replace though.

Thanks Robby,I sent him a inquiry about the manifold. Ike, I have a flapper coming so I guess I'll cut the rivets off on one bracket.Maybe I can pull the flapper out sideways and not have to take but one bracket off. I guess I can reinstall the bracket with 3/16" steel rivets?? jim

Could be wrong,but I don't think this manifold is original. Ike,seems like everything I have to work on is a bitch anymore You wouldn't believe how I had to rotate the manifold completely vertical on the rear stud in the head to remove it. Plus I had to notch the fiberglass behind the rear seat for clearance.

Oh yeah. These old engines can give you lots of surprises. The first was I had one bolt on the manifold that wasn't quite long enough to grab the threads. So I had to buy a stud, threaded on both ends, 1/2 inch longer, and put on a nut and a locking washer.

The next was that flapper. The engine ate it. It was in hundreds of pieces. So I had to clean out the exhaust. There were several other little time bombs waiting for me. A 40 year old engine can be tough to work on. But fortunately they are simple compared to modern engines and all you need are hand tools. You don't need a computer.

I kept a log. I suppose I should publish it.

I'm thinking that my flapper has been gone for a good while. I think I can use my elbow.It seems to be in good shape. I'm starting to understand Robby's point of view on stern drives a little better . I think highly of the 250 chevy 6.The rest of it is a necessary evil LOL. Ike, You ought to post your log for the poor souls(like me) that have yet to wander down the treacherous path of sterndrive repair.

Ike wrote:

By the way, i tried to replace the flapper valve and it was a disaster. I talked to a Mercury Marine technician and he said "leave it out. It's not necessary" Well.... maybe on my boat. It runs fine and I don't get any water being sucked in, but that might not be right on yours. It is a bitch to replace though.

Ike,when I want to stop the funliner from WOT,I pull the throttle to neutral. On the Nineteen I/O, you do that ,a little water will splash over the transom A surprise for my son setting in the back, last year . So I'll feel better with the shutter installed. I've got everything ready for the new stuff to go on. Just going to shop around for a manifold. Thanks for your tip on go2marine. I have one book marked i found for $399 plus shipping. I'm in no hurry though.

I've never been a fan of stern drives. Frankly I've always been a sailboat person (blasphemy!!!) However this one has lasted 42 years so it can't be all bad (LOL) I like the engine though. The old GM 250 was, and still is, a workhorse. They put millions of these in trucks. It runs well, has lots of power and is relatively easy to work on. There are plenty of places to get parts, even the marine parts. I would highly recommend going to electronic ignition. I bought a new Mallory distributor from summit racing. It works great, and I no longer have to adjust timing or dwell or any of that stuff. I also got a new coil but it was not good. I had lots of problems with backfiring and stalling. But when I re-installed the old coil those problems went away. Summit refunded my money. They are a good outfit.

Mine has a Rochester Carb. I don't like it much. I had it rebuilt but it still has a flat spot at about 1000 rpm and I have to jiggle the throttle to get past it. But below that and above that it runs great up to WOT. I may replace it with a Holley. But since I use the boat for fishing I spend most of my time at low rpms and it runs fine.

The stern drive is the old original mercruiser. I don't do sterndrives (just like I don't do transmissions) I took it to a repairer and they rebuilt it and so far so good. No problems at all. I had to clean up the wiring to get the trim and tilt to work properly but that's all.

I did a thread on this at www.fiberglassics.com/fiberglassics-forums/home/main-forum/just-bought-a-1972-sea-ray

I have a website that tells the story on this boat newboatbuilders.com/pages/SeaRay190.html

Id agree on the flapper. Usually the reason they get eaten is that the engine gets overheated. IMHO, especially in salt water, or anywhere where you can get some big waves up to/over transom they're cheap insurance for your engine.

My flappy flapper came today. I put it in this evening. I had originally thought I'd rivet it back in as factory,but studying it for a minute, I realized there was no way I was going to get my rivet gun in there... DUH. So I used some stainless screws with nylon lock nuts. Now just waiting on the manifold to get here. I decided to go for the $399 one on ebay. Every other one I looked at was at least $100 higher and I figured they were not going to get any cheaper the closer we get to spring. Now I guess I'll find one for $200 with free shipping LOL.

I had to trim the sides a little for it to clear the side brackets and shut as it should.

Looks good. Better than mine did. I hope it works ok.

Manifold came yesterday and I got "the beast " on tonight. That's a heavy SOB. Had to put the back stud in the head, gasket on, then manifold in vertical position and hinge the back end up into the elbow. The only way to do it. If salt water eats the manifold up every 3 years, I "guarantee" the Nineteen will be a fresh water boat while I own it LOL. The cut out place above the elbow was done by the manufacturer I guess.

Glad to see you got her back together Jim, looks good! Now all we need is some warm weather.

Looks better than mine. Good job.

Another way is to tie it to a 2x4 lay it across the boat sides. Get it close enough but a little low, then shim up the sides until aligned. They way I did my 350 I/O. Yep, HEAVY!

Also those who run salt, NOW is the time to install some type of flusher and run Saltaway after use. It won't remove rust/corrosion old stuff(but helps), but on new? I did that on new mans and 3 years after looking in the drain holes still looked damn clean. So works best on new only.

BTW, where did you get the manifold from?

Robby321 wrote:

Another way is to tie it to a 2x4 lay it across the boat sides. Get it close enough but a little low, then shim up the sides until aligned. They way I did my 350 I/O. Yep, HEAVY!

Also those who run salt, NOW is the time to install some type of flusher and run Saltaway after use. It won't remove rust/corrosion old stuff(but helps), but on new? I did that on new mans and 3 years after looking in the drain holes still looked damn clean. So works best on new only.

BTW, where did you get the manifold from?

Robby,I got it off of ebay. It's a Barr manifold MADE IN USA. Appears to be pretty good quality. Noticed that it was actually painted inside and out. Might have been dipped. I'm going to use the Saltaway on the ole Johnson and the Aristo funliner/trailer. She'll be the one I take to the coast.She's made many trips there in the past.

Barr makes good mans. Good Luck with it and the boats!

Thanks Robby, I appreciate that.

From Ikes post


Mine has a Rochester Carb. I don't like it much. I had it rebuilt but it still has a flat spot at about 1000 rpm and I have to jiggle the throttle to get past it. But below that and above that it runs great up to WOT. I may replace it with a Holley. But since I use the boat for fishing I spend most of my time at low rpms and it runs fine.

Ike, there is two settings on the accelerator pump on that Rochester 2GV, you may have a weak pump or you may have to select the hole on the linkage that gives you a longer stroke.