Merc 420 Cyclone engines

[BDC1013]

Jim

I have 4 complete sets of gil manifolds and 3 sets of tailpipes. 1 set off the 420's was stolen out of the boat many years ago. I'm wondering if selling all of this would get me anywhere close to having full custom pipes made? Does anyone buy this stuff anymore? Probably the least expensive way would be to rework the ones i have here in these photos. I have a friend capable of the fabrication, he just hasn't ever done a water jacketed pipe before. I suppose going to YouTube and looking at how that's done would be worth a look.

Yours look like probably what I would need mine to look like. i definitely don't want to move where the exhaust exits on the transom.

 

[fund razor]

I have two sets of Gils just like that, plus a pump and four mufflers and I can't give them away and they are sitting outside by my trash.

I think I have been trying for five years. I will probably recycle them.

Maybe in your area they would be easier to sell. Nobody here wanted them, either.

 

[BDC1013]

Im thinking i can cut on the second weld to the right in this photo, put that 45 on there and reweld that straight part to the end of the 45 that would put me pretty close. Does that make sense in writing or should i draw on the photo? haha

 

[MOBILEMERCMAN]

Tough call. You want as few bends and welds as possible. Welding pipes is a specific skill. Tail pieces or any exhaust for that matter that leak can ruin an engine. Its worth getting your fabricator to look at them. From what I've learned over the years is that it can be difficult to fix or modify pipes. I'm told the material can go away as you weld. I small crack can turn into a big hole.
Mine best I can tell were once a shelf item stock bravo tail piece extended with a non jacketed tube. They had a standard height like mine. a 3" and 6" taller rise. Yours appear to be one of the taller sets.
Look at the drawings on link I shared and try to confirm what you actually need to hunt for. The straight line from flange to center of hole is the important dimension. There is a little adjust in the hose where you extend it.
You can NOT bring the water dump inside the pipe closer to the manifold. And there MUST be a drop in pipe the entire length. And MUST have a flapper either internal or external.

 

[MOBILEMERCMAN]

Before I raised and re rigged my tail pieces had a wedge installed where the gaskets go to raise exit end of pipe up to go through existing holes. When I raised my X and engines I removed the wedges and pipes lined up nearly perfect. Maybe I still have the wedges. It wont fix your current issue but may help at some point.

 

[sonicss31]

Might want to mock up everything you want to do using 4” PVC pipe/fittings from transom to the first weld on the tail at the manifold. Then send them out to Hardin, CMI or Stainless Marine to have them custom made. It’s going to be pricey but worth the piece of mind knowing the motors don’t get water in them. :sifone:

 

[rschap1]

Maybe you could get lucky, start posting, and find someone that has what you need and needs what you have... trade risers.
Would be nice if possible.
Good luck

 

[BDC1013]

Tough call. You want as few bends and welds as possible. Welding pipes is a specific skill. Tail pieces or any exhaust for that matter that leak can ruin an engine. Its worth getting your fabricator to look at them. From what I've learned over the years is that it can be difficult to fix or modify pipes. I'm told the material can go away as you weld. I small crack can turn into a big hole.
Mine best I can tell were once a shelf item stock bravo tail piece extended with a non jacketed tube. They had a standard height like mine. a 3" and 6" taller rise. Yours appear to be one of the taller sets.
Look at the drawings on link I shared and try to confirm what you actually need to hunt for. The straight line from flange to center of hole is the important dimension. There is a little adjust in the hose where you extend it.
You can NOT bring the water dump inside the pipe closer to the manifold. And there MUST be a drop in pipe the entire length. And MUST have a flapper either internal or external.

Jim, I have been trying to read and learn all about reversion. I believe I get the concept. I read about these 540 engines and they do say you need to idle them no lower than 750rpm or they will start to suck water in. With the velvet drive transmissions I should be able to idle them a bit higher without any banging into gear right? Also I hear you on the drop in the pipe the entire length. Don from High power marine couldn't stress that enough to me when I was running my exhaust issue across him. I contacted CP Performance out here in Santa Rosa, CA and they sent me over the Hardin Marine 4 page exhaust build diagram for collecting measurements for a new set of tail pipes. I'd imagine this isn't going to be cheap. Probably looking at around $8k for both engines to receive new tailpipes?

 

[BDC1013]

Maybe you could get lucky, start posting, and find someone that has what you need and needs what you have... trade risers.
Would be nice if possible.
Good luck

Hard to say what exactly I need at this point but its been confirmed that the two sets I have are for a Bravo drive setup. I need to go take measurements. Sounds like a long shot that someone would need what i have and I need what they have... as my boat is kinda an odd ball unit :huh:

 

[MOBILEMERCMAN]

I idle my 509's about 1000. works out to be about 750 / 800 in gear. Being a particular old fart I have me routines. Adjusted mine to idle relatively low. My reasons to keep on low side are to be easy on trannies and around the dock. Your trannies are pretty tough design but, reverse is the weak part. I try not to use throttle in reverse. As soon as I clear the dock I bring the idle in gear up to 900 or 1000. I try to never let it idle below that. It will but, I just don't let it.

After you go through the measure process hopefully you find there is a stock shelf part that works and you can save time and some money. It will hurt nothing to have regular hard wall wire exhaust hose to connect a bravo length pipe to your thru hull tips. Provided the tail pieces are pointing the right direction. The rubber hose will allow a little mis alignment.

 

[MOBILEMERCMAN]

Looks like the pipes you have now will require hatch work. You should be able to have pipes fit under the hatch.

Your engines sure look nice. Keep up the good work. It gets frustrating one step forward two steps back. I know.... Its gonna be worth effort!

 

[BDC1013]

I idle my 509's about 1000. works out to be about 750 / 800 in gear. Being a particular old fart I have me routines. Adjusted mine to idle relatively low. My reasons to keep on low side are to be easy on trannies and around the dock. Your trannies are pretty tough design but, reverse is the weak part. I try not to use throttle in reverse. As soon as I clear the dock I bring the idle in gear up to 900 or 1000. I try to never let it idle below that. It will but, I just don't let it.

After you go through the measure process hopefully you find there is a stock shelf part that works and you can save time and some money. It will hurt nothing to have regular hard wall wire exhaust hose to connect a bravo length pipe to your thru hull tips. Provided the tail pieces are pointing the right direction. The rubber hose will allow a little mis alignment.

I prefer the sound of a high idle boat at the docks anyways so I'm sure ill turn mine up there. Ive been told my setup is pretty stout engines/trans/drives should last a while if maintained properly. I'm crazy about fluid changes and maintenance which is a good thing.

Looks like the pipes you have now will require hatch work. You should be able to have pipes fit under the hatch.

Your engines sure look nice. Keep up the good work. It gets frustrating one step forward two steps back. I know.... Its gonna be worth effort!

Yes, i tried to lay the hatch down over the engine. The spark arrestor hits it and the tail pipes are even with the spark arrestor. This is another speedbump im going to have to cross once the engines are in. I really dont want to get rid of the spark arrestors since they have the engine type and they look so nostalgic. I was thinking of raising the hatches somehow as there is a little room to go up. All the upholstery has been sent off to be redone so i dont really have a photo of how the back area is. I had planned to add some electric hatch actuators and raise them like a fountain from the middle up. They are currently just hand operated and hinged from the back.

These engines are literally barn find survivors. My uncle had them in a airplane hanger for many many many years. I believe these engines are from 2001, he bought them in 2005. They've been sitting covered in a garage ever since. If you remember the story of this boat being my dad's, this uncle is his brother. He turned 80 two weeks ago. There is so much sentimental stuff going on here... its very stressful. I have to finish this project SOON.

 

[MOBILEMERCMAN]

I love your back story. I have a special place in my heart for multi generational one family boats.

 

[MOBILEMERCMAN]

After just looking at first pic of this thread, I see the original tail pieces with mufflers built it. I believe it is more likely then not they are stock once off the shelf pieces. I hold hope once you go through the measuring process you'll find you can use a stock dimension pipe and not need a custom set built.

 

[BDC1013]

I love your back story. I have a special place in my heart for multi generational one family boats.

This boat has been in the family since i was probably 7 or 8 years old. Its so crazy looking back on the posts what i went through to keep this thing in my possession while going through college. Barely able to pay rent and this offshore boat is in the driveway HAHA.

For my family this boat means a lot. I too went through this thread and am amazed its 10 years old.

After just looking at first pic of this thread, I see the original tail pieces with mufflers built it. I believe it is more likely then not they are stock once off the shelf pieces. I hold hope once you go through the measuring process you'll find you can use a stock dimension pipe and not need a custom set built.

I have two of the original tail pipes. I recall fitting them on the manifolds in the garage and they weren't much better than the bravo tails. I will go ahead and place them on the manifolds now that I have an engine in and take some photos. I'm not pleased about mufflers as I watch way too many dock idling/start up videos for my own good!

 

[BDC1013]

After just looking at first pic of this thread, I see the original tail pieces with mufflers built it. I believe it is more likely then not they are stock once off the shelf pieces. I hold hope once you go through the measuring process you'll find you can use a stock dimension pipe and not need a custom set built.

You were right about these fitting much better. The only thing i see is they are off center (about an inch). These tails were from the starboard engine and im placing them on the port side. I have no clue if they are off the shelf units but at least I now have the angle i need. I have a feeling these will fit the starboard engine perfect and that its a shame I dont have the second set!

 

[MOBILEMERCMAN]

Sweet. Major progress. I suspect there are a stock configuration. Its also likely yours and mine are stock pipes for transmission engines. Bravo pipes are shorter.

Knowing that should make it easier to search for what you need or to buy a set. The rubber hose will allow a little mis alignment.

 

[MOBILEMERCMAN]

Your new 540's are a bit wider then the original 420's. That may be the difference. Check your engine center to center on transom assemblies. Probably 35 inches. Hopefully. Mine are 33 inches. My manifolds touch. If yours are less then 35 there may be another problem.

 

[BDC1013]

The part number I read on the original tail pipes is 844418-A1. In doing some research these look to be a bravo tailpipe part number as well?

This website shows the different exhaust pipes available during this time. https://www.boats.net/catalog/mercu...rndrive/2000/4ea9051nh/exhaust-manifold-elbow

20TAILPIPE ASSEMBLY, EXHAUST *{(Standard) (Driveline Models)}*
818495A1Unavailable

THIS one seems to be the one i need to hunt down

20TAILPIPE ASSEMBLY, EXHAUST *{(6.00 Inch) (Driveline Models)}*
818497A1Unavailable

20TAILPIPE ASSEMBLY, EXHAUST *{(3.00 Inch) (Bravo Models)}*
818499A1Unavailable

20TAILPIPE ASSEMBLY, EXHAUST *{(6.00 Inch) (Bravo Models)}*
818500A1Unavailable

20TAILPIPE ASSEMBLY, EXHAUST *{(Standard) (Bravo Models)}*
844418A1Unavailab

BUT this one is the same part number on the the tail set I have. My boat is not setup for bravo its a driveline model.
Maybe when they built the boat they took the Bravo exhuast from mercury that came with the engines and modified it? Maybe thats where the mufflers were introduced?

https://www.crowleymarine.com/mercury-outboard/parts/949_130.cfm This website shows what seems to be a mufflered tailpipe with another new part number. 42-818608A1

http://www.mercruiserparts.com/bam/subassembly/31307/949/130

Maybe i can find someone who has a set of these laying around? Maybe i can recreate them since i already have a set? This is all stainless material and then coated? Then polished when finished?

 

[BDC1013]

Your new 540's are a bit wider then the original 420's. That may be the difference. Check your engine center to center on transom assemblies. Probably 35 inches. Hopefully. Mine are 33 inches. My manifolds touch. If yours are less then 35 there may be another problem.

34 and 1/8 center to center. Also the manifold doesn't cross over center. It looks as if there may be 1 inch between the manifolds when the other engine is in. The muffler pipe has got to go though, that crosses over center. I now have a reason to have loud asshole guy exhaust :cheers2: