1984 Mercruiser 470 3.7L 180hp-Help!

[mshiff62]

1984 Mercruiser 470 3.7L 180hp

So I just bought a boat with this motor. Its in great shape. Just a few questions!

1) What spark plug is the correct number (seen too many diff ones)
2) What is the correct gap?
3) What oil should I use, I heard 20w-40? How much does it take?
4) How do I change the oil and filter? Any tricks or tips?
5) ANYTHING special I should know about this motor?

Thanks guys!

 

[500dollar744ti]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

5) ANYTHING special I should know about this motor?

There's lots. I am probably not the best person to outline all the oddities but I know a few.

-It's Mercury Marine designed and produced 4-cylininder aluminum block with single Ford 460ci head on it. So unique aluminum block with a cast iron Ford big block head on top.

-Engine is fresh water cooled, not raw water.

-Engine has not been produced for over 25 years, parts getting harder to find.

-Alternator is not accessory mounted but integrated in the engine at the front of the crankshaft.

-I think the cam drives the water pump and even though it's double sealed, it can leak and sometimes the cams have to be sleeved for new seals

I'm sure there's more but not having ever owned one, that's all I can think of. It's not a terrible engine, though some will tell you it is. They make a lot of power and can be reliable if maintained properly. Good luck with it.

 

[alldodge]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

how about going here and find your engine then look it up. Once your done if you have any other questions let us know.
Boatinfo - The library, containing manuals, brochures and other technical documents from the last hundred years!

 

[achris]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

1984 Mercruiser 470 3.7L 180hp

So I just bought a boat with this motor. Its in great shape. Just a few questions!

1) What spark plug is the correct number (seen too many diff ones)

AC-R42TS or NGK BPR6FS

2) What is the correct gap?

0.035"

3) What oil should I use, I heard 20w-40? How much does it take?

Mercury recommend 20W-40 or 20W-50. 5-1/2 quarts (with filter)

4) How do I change the oil and filter? Any tricks or tips?

You can either dump it in the bilge or suck it up through the oil dipstick tube (tube goes all the way to the bottom of the sump). Filter, just spin it off and spin a new one on.

5) ANYTHING special I should know about this motor?

Thanks guys!

Just to add a few more comments about the quirks of these engines... They have an 'open deck' block and so if you overheat them, say 'Good-night Gracie' to the head gasket.

If you have the 3" heat exchanger, be religious on having it cleaned out every couple or 3 years, and you absolutely must replace the water pump impeller (in the drive) every year. Oh, and if you don't use the boat very often, the impeller still needs to be done.

Also check your exhaust elbow every couple of years, with a view to replacing it about every 5-6 years....

If you don't have an external alternator (still using the original stator in the front pulley) then be prepared to be changing that out at some time.

Can't think of anything else at the moment...

Chris.....

 

[a1nowell]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

mshiff,
Welcome to the forum and to the club of 470 owners.
The things mentioned in other post are getting you on the right track. The oil filter you will need is a Fram PH5 (old number) and I use straight 40 weight oil but it is never on the shelf, I have to ask for it at the auto parts house.

As mentioned before, look at your engine if you have an external alternator then you have had the conversion if not you will sooner or later. wwwbreezeworks.net makes good kit at a reasonable price.

DO NOT LET YOUR ENGINE OVERHEAT if the temperature approaches 190 + degrees head back to the dock.

In future post you will get more specific help if you will post your engine serial number and your stern drive serial number. My engine serial number is located on the decal on the valve cover as well as stamped on the right side of the engine about 2/3d's of the way back. The stern drive serial number is stamped in the housing about 1/2 way up but I cannot remember which side.

The 470 is a powerful 4 banger if maintain correctly.

Larry

 

[stonyloam]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

If you take it out for a ride before the end of the season watch that temperature gauge like a hawk. When you go to winterize all you need do to freeze protect is check that the antifreeze is about 50/50 automotive, pull the aft drain plug on the heat exchanger and drain the raw water, that is it. I do it right on the ramp when it is pulled for the season. Pull the transom plug and let er drain. When you get a chance pull the outdrive, lube the U-joints and driveshaft and change the impeller and the pump housing with OEM Mercruiser parts then you will know you are in good shape in the spring.

 

[mr 88]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

Just looked over a boat with a 1979 470. There was a elbow at the end of the exhaust manifold and that had a drain plug on the bottom of it in it. I also think I saw a drain bolt on the bottom of the exhaust manifold near the middle. If yours has those I would recommend removing them and poking a coat hanger in the drain holes,make sure there cleared of metal crust..

 

[achris]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

Just looked over a boat with a 1979 470. There was a elbow at the end of the exhaust manifold and that had a drain plug on the bottom of it in it. I also think I saw a drain bolt on the bottom of the exhaust manifold near the middle. If yours has those I would recommend removing them and poking a coat hanger in the drain holes,make sure there cleared of metal crust..

Don't remove the one at the bottom of the manifold. The manifold is part of the freshwater cooling side of it, cooled by the same water as the block and head....

Chris.......

 

[mshiff62]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

Thanks for all the replies guys! I greatly appreciate it. So what is the heat exchanger and how do you drain it? Anyone have pics of it? I have a tank on top my motor that has coolant in it, then a small clear tank down near the oil pan that has coolant in it..I'm a little confused.

I also dont know what the temp is, because none of the gauges work at all! I'm gonna try to figure that out soon though.

I do not have a external alternator, why would I need that? What is wrong with the one built in?

I took it out tonight for a few minutes, let it run with the old gas, put stabil in it and a little fresh gas, and let it idle on the trailer for about 15 mins. It seemed to stall out everytime I put it in reverse, until finally I eased it and it went. Then I ran it and it was ok. Does anyone know if I should replace or clean the fuel filter maybe? Any other suggestions. I figured I would try to run it with the old gas and plugs and oil before I changed it all. Thanks all!

 

[mshiff62]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

I will get numbers tomorrow, but it has a Alhpa 1 outdrive. Any good write ups on replacing the water pump impeller, it was pushing water out good when I was running it with the hose and muffs though. I want to replace it to be on the safe side.

 

[stonyloam]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

When you go to winterize all you need do to freeze protect is check that the antifreeze is about 50/50 automotive, pull the aft drain plug on the heat exchanger and drain the raw water, that is it. I do it right on the ramp when it is pulled for the season. Pull the transom plug and let er drain.

Guess I should repost this.......

 

[stonyloam]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

Thanks for all the replies guys! I greatly appreciate it. So what is the heat exchanger and how do you drain it? Anyone have pics of it? I have a tank on top my motor that has coolant in it, then a small clear tank down near the oil pan that has coolant in it..I'm a little confused.

I do not have a external alternator, why would I need that? What is wrong with the one built in?

The cooling syatem is the same as on your car, except the coolant flows through a heat exchanger instead of a radiator, and the antifreeeze in the block is cooled by water instead of air. The raw water flows back and forth through tubes in the exchanger and the antifreeze flows around the tubes where it is cooled. The engine waterpump pumps the antifreeze through the exchanger, and the outdrive impeller pumps the raw cooling water through the exchanger. The tank on top of the motor is the coolant reservoir, and the plastic tank is the expansion tank, same as on your car. You only need to drain the raw water side of the exchanger.

The original rotor stator charging system works well, except it will eventually fail and it is VERY expensive to fix, so if it does fail most folks replace it with a regular marine alternator. So don't worry about it till it fails. When it does the Breezeworks Breezeworks kit works pretty well

Here is your manual: Boatinfo - Mercruiser Service Manual nr. 8 - 1985-1989 - Mercury Marine 4 Cylinder Engines and your outdrive: Boatinfo - Mercruiser Service Manual nr. 6 - 1983-1990 - R, MR, Alpha One & Alpha One SS Sterndrives

Welcome to the "470 Club":facepalm:

 

[mshiff62]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

Thanks for the help! So I took the boat out, and none of the the gauges work. Has anyone experienced this? I think it may be something to do with that circuit breaker in the back. Im not sure, any help is appreciated!

 

[stonyloam]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

Look on your manual, about page 177 for diagrams. On the Mercruiser the purple wire is ignition switched 12V. In other words when the ignition switch is turned to on there is 12 V on the purple wire to ignition and accessories. So get yourself a digital voltmeter and turn the ignition to "on". Check the voltage on the instrument purple wires. There is an ignition fuse, but if the boat runs that is probably OK. There might be an accessory fuse for the instruments. Good luck.

 

[achris]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

Thanks for the help! So I took the boat out, and none of the the gauges work. Has anyone experienced this? I think it may be something to do with that circuit breaker in the back. Im not sure, any help is appreciated!

Does the engine run?

 

[mshiff62]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

The motor runs fantastic. Lots of power and in excellent condition, achris!

Ok guys, lots of corroded wires, broken wires, and all kinds of mess. Pulled all the wires out, gauges, etc. Got a volt meter and lots of connectors, dielectric grease, wire, etc. Got a new fuel tank sending unit (extreme corrosion), needless to say, now all my gauges work. What a job, but now all the wires are neatly redone and very easily accessible in the even of replacing something. I even replaced the MPH "fin", and tubing to the mph gauge.

The only thing that doesnt work is the trim gauge. Grrrr.

Now, on each sides of the outdrive on the "horse coller", there are small round plastic things with wires attached to them which is for trim position and trim limit. The wires were broken off, and I decided to go ahead and order new ones. Now, I'm not sure what wires to connect them to once I put them on.( I do have a green w/ white stripe and purple w/ white stripe wire coming off the wiring pack from the pump and gauge) And I'm hoping this makes my trim gauge work, as these wire are not hooked to anything. Green and white comes off of pump and purple comes from 4 stranded wires coming from throttle control. Also, my "up" portion of the swtich on the throttle doesn't work, only the down, but the "trailer" button (trim override) does work so thats how I'm getting it to go up. Could this be because of those trim position and limit sensors or could it be the switch in the throttle just doesnt work when pressed "up".

Anyone had this issue? I'm slowly working all the bugs out. I spent all weekend working on this thing, only spent $400 so far on parts, and got the boat for a good deal so I'm not complaining!

 

[achris]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

...The only thing that doesnt work is the trim gauge. Grrrr.

Now, on each sides of the outdrive on the "horse coller", there are small round plastic things with wires attached to them which is for trim position and trim limit. The wires were broken off, and I decided to go ahead and order new ones. Now, I'm not sure what wires to connect them to once I put them on.( I do have a green w/ white stripe and purple w/ white stripe wire coming off the wiring pack from the pump and gauge) And I'm hoping this makes my trim gauge work, as these wire are not hooked to anything. Green and white comes off of pump and purple comes from 4 stranded wires coming from throttle control. Also, my "up" portion of the swtich on the throttle doesn't work, only the down, but the "trailer" button (trim override) does work so thats how I'm getting it to go up. Could this be because of those trim position and limit sensors or could it be the switch in the throttle just doesnt work when pressed "up".

Anyone had this issue? I'm slowly working all the bugs out. I spent all weekend working on this thing, only spent $400 so far on parts, and got the boat for a good deal so I'm not complaining!

Right.... The trim limit and the trim gauge are separate issues. Let's deal this them one at a time.

Trim gauge. The sender for the gauge is on the starboard side of the gimbal ring (horse collar). The wires run through the gimbal housing and into the inside of the boat. Somewhere near the back of the engine you'll find a pair of wires, one black, one brown/white (maybe a different colour as this was the era Merc changed to BIA colours). Once you install the new sender, connect the sender wires to these two wires (doesn't matter which to which)....

Trim limit. The lack of a trim limit switch is why you UP button doesn't work. Without the limit switch connected the circuit thinks the limit is reached, and will only allow you to use the trailer button to raise the drive. Again, when you install the new limit switch (port side of the gimbal ring) connect the 2 wires to the purple/white and the blu/wht... Doesn't matter which to which...

BTW, when you receive the new senders, they come with all the wires attached. DON'T try and cut the wires and join them to the old ones. Many people try that and it does NOT work. You need to do the job properly, take the old ones out and fit ALL of the new ones.... Yes, getting the wires in through the aperture in the gimbal housing is not easy, and getting the plate off and back on (that holds the sealing part of the wiring in) is also not easy, but it must be done that way. NO other way works. They have all been tried... :facepalm:...

Chris.......

 

[stonyloam]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

Know what I would do? This winter I would pull the outdrive and the bellhousing and change the driveshaft bellows, the the shift cable and bellows, and change the trim limit and sender at that time. If the exhaust bellows are not torn I would reuse it, and put the savings toward OEM bellows and cable. Oh yeah once you get the trim sender to work, never look at the gauge again LOL, learn how to trim by feel, and believe it or not the tachometer.

 

[achris]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

Know what I would do? This winter I would pull the outdrive and the bellhousing and change the driveshaft bellows, the the shift cable and bellows, and change the trim limit and sender at that time. If the exhaust bellows in not torn I would re use it, and put the savings toward OEM bellows and cable. Oh yeah once you get the trim sender to work, never look at the gauge again LOL, learn how to trim by feel, and believe it or not the tachometer.

First class advise right there....

Here's the numbers for the transom seal kit .... Gives you everything you need to do the job...

Transom seal kit: 30-803097T1 (includes all 3 bellows, a water hose and a gimbal bearing and a drive gasket)
Shift cable kit: -865436A02 (all parts for the cable, but no bellows, they are in the above kit)
Trim senders kit: -805320A03

While you're in there, check you have the late style upper shift shaft seal kit... (23-805041A2). The upper bushing (with seals in it) looks like this... (the one on the right. The one on the left is the lower bushing)

As much as I like to promote iBoats sales, with bellows and shift cables, OEM only!

Chris.........

 

[mshiff62]

Re: 1984 Mercruiser 470 3.7L 180hp-Help!

Thanks so much for the help guys! Ok so let me get this straight..

Blue/white wire and purple white wires off of pump get connected to the 2 wires from the Trim limit sensor, and it doesnt matter which ones connects to which from the sensor.

Ok, I found a brown and white coming off a coil of wires going to the back of the 50amp breaker in the back, not the front where the plug is, but behind. It is attached currently to a small step block on the front of the circuit breaker. I dont see a black wire, is that just a ground coming off the motor? If so, can I just ground it to the bracket on the circuit breaker? I think I have the trim limit part down, a little confused about the gauge. The wire coming off the gauge is a white w/ pink stripe wire, that is attached to the sender terminal. When I trace that wire it goes into that same coil of wires that the brown and white wire is coming out of. Here is a picture to help.. I am ok with wiring but get a little lost sometimes. Thanks again guys, you all are a great help, worldwide at that, mate! I am in South Carolina so we have warm weather for a while, still time to play with the boat!