Mercruiser 4.3 How do I check it out before running it?

[firemedicmonkey]

I recently acquired a boat with what I believe is a 1995 Mercruiser 4.3 Engine with an Alpha outdrive. I don't know much about boats. I have driven them and I work on Jet-Skis but I don't know much about boats.

The boat has been sitting for about 2-3 years and has not been run at all in that time. I am not sure if it was winterized properly or not.

What should I do to check it out before trying to start it / run it.

I would assume oil, plugs, etc on the motor, what else can I do to find out what I need to get this thing running?

I will get exact details tomorrow but I am hoping for a little help now so I can decide whether it is even worth the time and gas to pull this out of where it is sitting and back to my shop.

 

[ken_23434]

Re: Mercruiser 4.3 How do I check it out before running it?

I would look at the oil and see if it has water in it. This goes for the engine and the outdrive.

After sitting that long without running, the carb is likely in the need of a rebuild. The old gas in the tank (if it was stored with gas in the tank) will end up causing problems too. Drain all the gas possible from the boat. Disconnect the fuel hose at the fuel pump, raise the front of the trailer as much as possible and get that old fuel out of there. New fuel filters are in order too. If it doesn't have an inline water separating fuel filter, that would be a good addition. Those filters are bigger, filter more, and are much easier to change out. If you have crud in the fuel tanks, fuel filter changing will be common.

Pull the plugs and look at them. If they have rust on them, that might mean some sort of problem leading to water in the cylinders (crack somewhere, seawater leak in exhaust...)

While the plugs are out, I would spray some fogging oil in the cylinders and let it sit a while. This will help lube the walls and rings. Try to crank it. A compression test will give you a lot of info about condition of the motor.

Never run the motor without the "muffs" on the outdrive providing it water.

The impeller in the outdrive shoudl be replaced prior to running the motor any long amounts. Test firing it should be OK. The cooling water supplied to the engine originates from the outdrive, via an internal water pump. That impeller goes bad after a few seasons. If it has sat for a long period, the rubber impeller is likely to have lost some of its flex, and will eventually fail. Replacing it is not too hard.

External check of the engine for wiring that is faulty, anything "suspect" with fuel system, signs of leaks, core plugs dislodged...

My 2 cents...

 

[firemedicmonkey]

Re: Mercruiser 4.3 How do I check it out before running it?

What the best source for parts for these engines and outdrives ?

What you said is along the lines of what I was thinking. I am pretty handy as a Auto Mechanic and I do a lot work on PWC's so I am not a complete idiot just the little tricks and tips for big boats and out drives etc.

Is there a thread on here about replacing the impeller?

What is the best source for a repair manual? OEM, Haynes etc?

 

[fuzzybob]

Re: Mercruiser 4.3 How do I check it out before running it?

You can go to the "Adults only" sticky at the top of the forum and get lots of info... you can also download the merc shop manuals for your engine and out drive thanks to Don S

 

[firemedicmonkey]

Re: Mercruiser 4.3 How do I check it out before running it?

Thanks for the input Guys!

The first place I went was the adults only section. I downloaded what I think is the right engine manual. And I have been reading it. I am pretty confident on the engine stuff. Like I said I work on cars and Jet-Skis so motors aren't to big of a deal.

Its the outdrive and other boating stuff... i.e. trim, bilges etc that I am not to sure about. I was reading about pressure testing the out drive is that something that I should do.

Is removing the outdrive and checking all the stuff u mentioned covered in the manuals that are on this site?

How hard is the alignment procedure?

 

[imported_TheMan]

Re: Mercruiser 4.3 How do I check it out before running it?

Everything is covered in the manual.

The alignment procedure is easy as long as you have the tool. Don't eyeball it.

Pressure testing the outdrive is a good idea while you have it apart so you can fix anything wrong. You can build your own tool to do this if you are so inclined and I think it is discussed several times on this forum if you do a search.

Most of the boat stuff isn't more complicated than anything else mechanical, you just have a lot more of it. Trim pump is simply a hydraulic system and has the same problems/trouble shooting of other hydraulics. You'll do fine. Just read the manual and take your time.. and don't take shortcuts.

 

[ken_23434]

Re: Mercruiser 4.3 How do I check it out before running it?

The alignment tool is basically a long metal rod with a specific diameter at specific points. It passes through the transom (gimbal bearing) and into the coupler at the rear of the engine. If the rod can easily slip in and out, then the alignment is correct. No rocket science with that check. You can only do the check if you have that rod, though. To adjust the alignment is a matter of turning a nut on the engine mount to raise or lower the front of the motor.

The outdrive stuff is covered in those service manuals. The engine will be in one and the outdrive will be in a separate one, though.

Pulling off the outdrive is litterally a matter of disconnecting the two trim cylinders (you can get away with just the rear bolts, hydraulic lines still attached) from the outdrive and then 6 bolts. So, 8 bolts total and you can pull it off. Oh, you need the throttle in forward before pulling it off. You will need a gasket kit, though. I try to keep a couple packages handy. I think they cost me about $7 at West Marine a couple weeks ago for a new set.

Trim: press the buttons on the dash or your throttle and the engine should go up or down. If it does, then you are good.

Bilges: If the boat is out of the water, don't worry about it while you are working on getting the boat running. Well, as long as the bilge is not full of water from rain (drain plug should stay out when boat is out of water to prevent it from filling with rain)

 

[jam1ej20]

Re: Mercruiser 4.3 How do I check it out before running it?

A boat that has been sitting out that long probably has some rot and wet foam issues. I would really consider all of the potential problems and pricing options before diving into something deeper than anticipated. Check the stringers and transom for rot. I'm currently rebuilding my own 1995 merc and have the motor all together after a new block swap (among many other things) and I'm doing fiberglass work because I found rotten stringers when I got ready to place the motor back in. I can probably answer most of your questions regarding that motor and drive combo. But, hey, I'll have a practically brand new set-up when I'm done. Best of luck!

 

[IVAZ]

Re: Mercruiser 4.3 How do I check it out before running it?

Bubba,
Kaw kaw? Thats hilarious.
Here is a link to a pump Ziggy made to test the outdrive.
http://forums.iboats.com/showthread.php?p=1573303#post1573303

Its in the "adults only" section. Take a look at that section. There is many well written how-to's.

 

[firemedicmonkey]

Re: Mercruiser 4.3 How do I check it out before running it?

what the best way to test for rot and foam issues? How do I go about it?

Where can I get or borrow one of those alignment tools?

 

[IVAZ]

Re: Mercruiser 4.3 How do I check it out before running it?

The tool is going to be hard to come by unless you know someone who has it. I bought mine on ebay. Where are you located? Maybe someone from iboats lives close to you that may have one.

 

[jam1ej20]

Re: Mercruiser 4.3 How do I check it out before running it?

To test for rot you can drill "core samples." Run a search here on the forums and you'll find all the info you need on this procedure. Just be preparred to properly seal the holes if the stringers turn out to be OK. If you've got stringer rot, you've got wet foam and if you've got wet foam, you've got rotten stringers.

 

[ken_23434]

Re: Mercruiser 4.3 How do I check it out before running it?

http://www.iboats.com/Mallory_Tool_...5561836--**********.316985114--view_id.363793

Here is one for sale from the host of this forum. They can be found other places too. There are a few "special tools" that are needed for boat work. So, if you DIY, you will need to fork up a little $$ upfront. But, when you compare the price of DIY with having a Marina do it, to me it's worth the price of the tool. Plus, the local Marina isn't necessarily always "local".

 

[imported_TheMan]

Re: Mercruiser 4.3 How do I check it out before running it?

There are several places where you can get the dimensions of the tool (including this forum) if you know a machine shop or feel like having one made.

Don usually has an image with the dimensions handy if you can't find it while searching the forums. If not, I've got it somewhere. I'm pretty sure the measurements are listed somewhere from what I remember though.. maybe the manual?

 

[ken_23434]

Re: Mercruiser 4.3 How do I check it out before running it?

I am fairly certain the dimensions for the alignment tool is in the sterndrive Service Manual.

I am sure it would be fairly easy for a machine shop to turn down a piece of round stock down to the dimensions. Not sure how much that stock would cost, though.

 

[firemedicmonkey]

Re: Mercruiser 4.3 How do I check it out before running it?

Ok sorry I have been AWOL for a minute I had work backed up that I had todo to keep the bills payed and get this adventure started. I took posession of the boat the other day and here is what I found:
It is a 1992 Bayliner with 4.3L Mercruiser Alpha I Thunderbolt IV Ignition
Engine Serial #: OD823128
OutDrive Serial #: OD760439

I downloaded manuals 7 and 14... Started reading have not come to the specs for the alignment tool. I think it might be cheaper to buy one then to take the time to find the stock and get it made.

Anyone found links on the specs for it though?

Anyone with tips, info, or links on how to check for rot?


What / where is the best source for parts? Cheapest / Best parts?

I read in the manual only straight weight oil, is that correct I have always used multi weight (10W40 etc)

 

[rewdan]

Re: Mercruiser 4.3 How do I check it out before running it?

hi, i have a 91 searay with a 4.3 v6 that got washed ashore and filled with sea water 2 years ago. We dragged it out with a tractor and got everything working again but I couldn't use it last year due to a new baby, it was fogged ect. This year the starter motor is full of rust so i have got a new one to fit but before i do.... I can turn the cam shaft freely with grips but not the crankshaft, shall i just fit and try the new starter motor or should i do something else? thanks

 

[cooter2506]

Re: Mercruiser 4.3 How do I check it out before running it?

rewdan start your own thread dont pull up and hijack an old thread.