Motor Redo!!??

pigrge · Mar 29, 2008

So I am restoring my 1982 Sea Ray with a Merc 120 in it. I love the motor because it gets done what I need it to get done without using a ton of 3.50 gas!!!! Anyways, I am doing the floor and the transom and has to yank the motor. The guy who I bought it off of said that something had happened where a nut was sucked into the intake and he replaced one of the pistons because of it. Not too sure which one, but judging by what appears and feels like a big gauge in the number one cylinder I would say that that is where the damage occured. Please look at the pics and give any recommended advice that you can. I LOVE this boat and am willing to spend the money to get it fixed. I am pretty sure that I should have the cylinders bored out. But are there oversized rings that are available for this motor? Also, look at the carbon on top of number four piston. What is happening in there? And last but not least, does it look like there was a leak between the water passage and the number one cylinder to anyone? Thanks guys! Waiting patiently!!

Bondo · Mar 29, 2008

Re: Motor Redo!!??

Ayuh,.....

Those are Rebuildable motors with the proper Over-sized parts,....
It looks like it'll need a .030 overbore,+ the related new pistons,+ rings....
#4 was taking on Water from somewhere,... that's why there's less carbon build-up there....

Drag the whole thing over to a Machine Shop,+ Ask them what,+ how much they'll do for you.......

rodbolt · Mar 29, 2008

Re: Motor Redo!!??

seeing as your redoing it anyway, the complete 3.0 long block isnt but about 1800 dollars, I find complete bob tail 3.0's for under 3000 occasionally new in the crate from merc. especially if its a saltwater motor. most likly culprit of water in #4 is the manifold and riser area.

pigrge · Mar 30, 2008

Re: Motor Redo!!??

So I found a long block 3.0 from Florida, the guy will give me for 1000 delivered. He guarantees that it will have good compression when I get it, and all I have to do is bolt on my alternator and distributor and starter. HE will give me an exhaust manifold, carb, exhaust riser, and head assembly. Is there anything that I should look out for?
Also, I wanted to ask this question a loooong time ago, but never did get around to it. My choke assembly on my carb, is a heat activated choke. It has a little pot on the top of the manifold that transfers heat to the carb choke and relives tension on a spring and thus opens the choke. I never liked this, is there another option? Thanks!

rodbolt · Mar 30, 2008

Re: Motor Redo!!??

the 3.0 carbs used an electric choke, you will have to modify the wireing harness, not hard.
make sure you get the 2 piece seal 3.0 not the 1 piece rear main or get the correct 3.0 flywheel.
they made the 3.0 in both a 2 piece and onepiece rear mains and the flywheels are not interchageable, some of the couplers are but not all.

Coors · Mar 30, 2008

Re: Motor Redo!!??

Make him show you 180 # compression.

pigrge · Apr 1, 2008

Re: Motor Redo!!??

180? The manual only states that it is supposed to be 140-150 Why 180?

make sure you get the 2 piece seal 3.0 not the 1 piece rear main or get the correct 3.0 flywheel.
they made the 3.0 in both a 2 piece and onepiece rear mains and the flywheels are not interchageable, some of the couplers are but not all.

What does this mean? How would he know? The guy that I am buying it off of has quite a few of these things sitting around in his shop. I want to be able to interchange basically whatever I need from my 2.5 except the carb. So what would I ask for? This flywheel issue worries me, and I dont want to have to update my coupler and all that. What needs to be done to the engine wire harness?

JustJason · Apr 1, 2008

Re: Motor Redo!!??

i don't think your going to see 180 pounds out of a 120/140..... but if your getting 130+ i'd say your in good shape.
what company in florida are you getting it from?
Is it DDADT?

pigrge · Apr 4, 2008

Re: Motor Redo!!??

Actually I found two more motors that are for sale locally with relatively low hours on them. But my main concern is going to be the exhaust. My current configuration is with the exhaust elbow coming straight off the back of the motor. And then down into the inner transom plate. The 3.0L motors that I am looking at both have a smooth round rise that come back at an angle to the motor. One of the guys has the part that actually connects to the inner transom plate. Are my exhaust tube and the new style exhaust tube that connects to the inner transom plate interchangeable? (Same bolt pattern on the transom plate?)
Also, aside from a small modification to the harness, will the newer style (1994) harness connector attach to the older style (1982) Any info would help ALOT!)

pigrge · Apr 11, 2008

Re: Motor Redo!!??

Any help on this motor will help. I went and bought the 3.0L from a local guy. The serial number is B916668. I noticed a few things that were different from my old motor. First thing, is the exhaust riser, please see above, still need some help with this problem. Second is the Electric choke. Does this have anything to do with the harness that goes to my dash? If so what needs to be done to hook this up? Third, is the difference in the shift/throttle assembly. My old one has the shift throttle assembly that is actually attached to the transom assembly at the top, and the new one sits on top of the valve cover. I believe that the carb assembly on the new motor is a mercarb, one throttle mixture screw, and my old one was the rochester, two screws. Is the linkage on the carb actually different? With the old carb, the throttle cable came from the back of the motor and actually attached to the exhaust maifold, and the new one I have NO IDEA where the throttle cable attached, it appears that it attaches from the top of the valve cover??? Anyone have some diagrams that will help with that issue? Thanks!

pigrge · Apr 12, 2008

Re: Motor Redo!!??

Any Love?

heyttown · Apr 12, 2008

Re: Motor Redo!!??

This is a great site with loads of free talent offered. Give it some time, Im sure some of the regulars will come around to offer some info.

As Mister Miagi would say!
Patience Dainielson

Coors · Apr 12, 2008

Re: Motor Redo!!??

Bumping you; old engine was rings shot; Don the guru can help you from here.

pigrge · Apr 15, 2008

Re: Motor Redo!!??

Bump

erikgreen · Apr 15, 2008

Re: Motor Redo!!??

I know this isn't a helpful comment, but personally I've been avoiding this thread, since every time I read "nut was sucked into an intake" I cringe

pigrge · Apr 15, 2008

2.5L to 3.0L Swap

2.5L to 3.0L Swap

Yeah thanks Eric, I cringe also, thats why I went ahead and replaced the whole dang thing!!!! I think I have found a solution, it appears that the exhaust riser from the old motor, goes straight back from the exhaust manifold will bolt right up to the new one. I will have to go out and verify tomorrow. I think I am going to keep digging trying to find some info on the swap. Any information from you guys on here that can help with this swap will be greatly appreciated! I will document everything that I do so I can add some information for others. There are two big questions that I have. One is the exhaust riser going to the old exhaust tube that mounts to the transom assembly. The old exhaust tube is mounted to the transom assembly with just three bolts. I looked at some parts diagrams and saw that the year of the motor, 1988 has an exhaust tube that mounts to the transom assembly with four bolts. Can I just put on the old riser to the new manifold and the old exhaust tube? Also, the shifter cables, and throttle cables. Can I use the old cables with the new set up? My old shifter cables were mounted to the transom assembly and the old throttle cable was mounted to the exhaust manifiold! What needs to happen here?

Bondo · Apr 16, 2008

Re: 2.5L to 3.0L Swap

Re: 2.5L to 3.0L Swap

One is the exhaust riser going to the old exhaust tube that mounts to the transom assembly. The old exhaust tube is mounted to the transom assembly with just three bolts. I looked at some parts diagrams and saw that the year of the motor, 1988 has an exhaust tube that mounts to the transom assembly with four bolts. Can I just put on the old riser to the new manifold and the old exhaust tube?

Ayuh,.....

It sounds like you're trying to put an Alpha dressed motor into a Pre-Alpha dressed boat,......
The only time I've done it was by swapping out the Whole Manifold to the 1 that fits the Mod.1 transom assembley......

Also, the shifter cables, and throttle cables. Can I use the old cables with the new set up? My old shifter cables were mounted to the transom assembly and the old throttle cable was mounted to the exhaust manifiold!

I believe that as long as your present upper cables are Long enough,....
You can just use the newer style shift bracket......

Without having Both motors sitting in front of me,.... It's alittle hard to tell Exactly what needs changing,.....
But,.....
I Do know that by using parts from both set-ups,....
You Can install the newer motor into your boat...........

pigrge · Apr 16, 2008

Re: Motor Redo!!??

Thank you sooo much for your posting Bond-O. Yes I believe you are right this is a pre-alpha boat, (transom assembly now) Would it help if I posted some pics? If so what would you need pics taken of? I can have them this evening! Thanks for the reply!

Bondo · Apr 16, 2008

Re: Motor Redo!!??

Ayuh,.......

Without rereading this whole thread,......

It's going to be easier to convert this new motor into an old motor, to marry it to the transom assembley,.....
Going the other way would mean a New transom assembley......

Is the complete Manifold,+ Riser from the 120hp still serviceable,..??
Is the Flywheel Cover still serviceable,..??
Is the Downpipe still serviceable,..??
Is the Shift Bracket,+ Cables still serviceable,..??
Is the Coupler still serviceable,..??

No pictures necessary just yet,..... The Answers to those Questions will get Us started.....

pigrge · Apr 16, 2008

Re: Motor Redo!!??

Okay, so here is the scoop on this whole scenerio, but first, bondo-o I HAVE to ask this this question, what does, Ayuh mean? I was in the Navy, and was around some salty old dogs, and never heard that word. I think it is funny, but just want to know what it means, with all due respect!
On to the topic. the complete manifold is not serviceable, the manifold is not serviceable, it was cracked along one of the exhaust ports. and the carb was JUNK!
From what I can see, the flywheel cover has no damage whatsoever.
The downpipe is still okay.
The shift bracket was great and the coupler worked when I took it out. What should I do from this point. Thanks again Bond-O.

Motor Redo!!??

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