Mercruiser GM inline 140 - need a good starting point.

[RTassi]

Mercruiser -- GM inline 140 -181 cid / 4 cyl.
Long story made short. I've been gifted a Wellcraft airslot that threw a rod 12 years ago - it was rebuilt, mounted back in place and then left sitting, under roof, for the past 10 years +_ All parts are there and were in working condition when re-built.

I'm no mechanic so i've asked a friend who custom builds engines to help with a play by play for me. He was concerned for b/c it's been sitting in Louisiana humidity for all this time. The game plane and my instructions were as follows:

Plan: see if the motor turns over before investing any time & money.

First Steps:
1. fill the spark plug holes with Reslone - small rust buildup was visible. Said when we turn it over it will Burp out so no worries there. My ignorance has me questioning everything...Is this a safe, common practice?

2. Test the Alternator at any Auto Zone store to see if it's good -- Tried that.. All auto stores look at it like it's foreign. I was told the problem was "there's no plug" to hook up to their machine... I called a local marine store and the mechanic said... "Yep, that's a problem" and left it on that note. Is there another option to test it?

3. Replace the fuel pump bowl & all filters - it was damaged but I could not get just the bowl from Sierra. i found a pump on ebay for $15 and it's on the way. 2 pumps 1 bowl.... anybody know where i can get just the bowl - seems wasteful!

Any recommendations before we give this a shot? spark plug wires look pretty bad-- thought about replacing them - I've detailed the Exhaust manifold, cleaning the rust, paint & grim off... just cosmetics really. New gasket kit maybe - most gaskets are there, some doubles... but I'm not sure if they have a shelf life.

Thanks in advance.

 

[a1nowell]

Re: Mercruiser GM inline 140 - need a good starting point.

RT,
The first step in you getting great responces from this forum is to provide as much engine info as you can. Starting with the serial number. This can be found stamped on a plate toward the rear of the engine block either on the left or right side depending on the model and year. My 470 also has it on a decal on the valve cover. As for the altenator, take it to a rebuilder, they can test it and if it is bad the can rebuild it, generally cheaper that buying a new or rebuilt altenator. As far as replacing stuff, I think I would wait and see if she fires up. Can you turn the engine over by hand with the plugs out? Besides boat repair shops I have found that NAPA stores have a good line of marine parts.

Good luck,

Larry

 

[Fishermark]

Re: Mercruiser GM inline 140 - need a good starting point.

it was rebuilt, mounted back in place and then left sitting, under roof, for the past 10 years ...

1. fill the spark plug holes with Reslone - small rust buildup was visible. Said when we turn it over it will Burp out so no worries there. My ignorance has me questioning everything...Is this a safe, common practice?

Before turning the engine over, I would strongly suggest priming the oil system first. You can remove your distributor and then remove the gear at the bottom - it will then become a priming tool. You can use a big 1/2" drill to turn the distributor and prime the oil system. Here's one I did a while back:

If this engine has never been run after being rebuilt I would have serious concerns about the rings being able to properly seat.... but I guess it is what it is at this point. You do not have much to lose. If it works, then great!

 

[tommy8604]

Re: Mercruiser GM inline 140 - need a good starting point.

i would start by removing all spark plugs and filling with something like Marviel Mystery Oil. then just try to turn it over using the crank bolt but be careful to not force it too much and break the bolt. If it turns over prime the oil system and turn it over with key with plugs out. if all is well then move on to compression test. if compression is good then to spark, and from spark to fuel. i left fuel as last because if its been sitting for 10 years you are more than likely going to have to put a little money in that area, prolly a carb rebuild, filters and possibly fuel lines,

 

[RTassi]

Re: Mercruiser GM inline 140 - need a good starting point.

Larry - serial # ??? I found the numbers 27700 stamped on the far-back left side up high (facing rear) and the #87 hand-etched afterwards... i was able to find the parts list on marineengine.com for
MerCruiser 140 GM 181 I/L4 1968-1972 > 2508261 THRU 3332137 which made it seem like the right one... and after perusing the parts all look like my motor...but when i plug in the 2770087 it is not an acceptable serial #. Re-builder told me in5 minutes that Alt. was good. Thanks. Any thoughts on the serial #???

Fishermark - I filled the crankcase and the plug holes with a mixture of Reslone and 10w-30 oil -- it's been sitting for nearly a week and last night i attempted to turn over by hand. How do i get an angle on the crankbolt? And to be sure i'm wrenching on the right bolt...Where is it exactly? i can only access the front and sides... i put a prybar on the engine mount and the pully under the water pump... got an 1/8 of a turn out of it before i got nervous and lost my landing spot for the prybar.... Any ideas?

should i take it out of the boat and rebuild it on a stand- exhaust manifold and all then re-install back in the boat? Seems much easier than this up and down i'm doing.

the beater i'm working on....

 

[RTassi]

Re: Mercruiser GM inline 140 - need a good starting point.

i would start by removing all spark plugs and filling with something like Marviel Mystery Oil. then just try to turn it over using the crank bolt but be careful to not force it too much and break the bolt. If it turns over prime the oil system and turn it over with key with plugs out. if all is well then move on to compression test. if compression is good then to spark, and from spark to fuel. i left fuel as last because if its been sitting for 10 years you are more than likely going to have to put a little money in that area, prolly a carb rebuild, filters and possibly fuel lines,

Tommy - mislabled my last response... you were who i was asking about the crankbolt etc...

 

[Fishermark]

Re: Mercruiser GM inline 140 - need a good starting point.

should i take it out of the boat and rebuild it on a stand- exhaust manifold and all then re-install back in the boat? Seems much easier than this up and down i'm doing.

From your picture, that's exactly what I would do if it were me. If you have an engine hoist it would take all of 10 minutes to pull that engine... and that's if you take your time.

Pull the outdrive first and then pull the engine. It will give you the opportunity to check your bellows and gimbal bearing - clean up your bilge - check your bilge pump - all the stuff that is more difficult with the engine in place.

 

[RTassi]

Re: Mercruiser GM inline 140 - need a good starting point.

10-4 Fishermark

Also found this last night... answered my own question about the serial #
"Mercruiser product serial numbers in the following format 0W555555 begin with the number 0 and not the letter O. However the site will automatically correct your input if you accidentally enter an O. Serial numbers that do not follow this format but instead have 7 numerical digits are prior to 1980 and cannot be searched on the Parts Finder. "
Under closer inspection the 87 that was etched at the end of my serial # was b/c the raised numbers had been worn off... guess somebody fixed it along the way.