Stuck 1970 Mercruiser 165 inline 6

[curliss]

First Post - I just picked up a 1970 Slickcraft SS-204 with the inline 6 165. It is a Michigan freshwater boat and always stored indoors. The boat is in beautiful condition and I bought it knowing it hadn't been in the water in 4 years and knowing I am facing a complete fuel system cleaning/replacement and could be facing a complete repower.

I have two questions:
1) The engine is stuck. It was drained, but apparently not fogged. Does anyone have a clever suggestion for loosening up the engine after soaking the cylinders. It doesn't seem like I can get to the crank pulley due to the front engine mount. I've read a suggestion to pull the starter and try to move it with the flywheel. - any other ideas?
2) The previous owner (whom I know and am 99% certain is a trustworthy person) stated it was running fine with no problems prior to storage. Assuming I loosen the engine, get it running, and the compression is good - is there any reason to do an overhaul (other than peace of mind)?

I am willing to pull the engine and overhaul it, but would obviously rather not if unnecessary. I just wonder if the cylinder rusting from a stuck engine would be significant enough to damage the cylinders, rings, etc. and I would be better off to do the overhaul now rather than damage the engine by running it (again, assuming I can get it running).

Thanks for your help.

 

[fishmen111]

Re: Stuck 1970 Mercruiser 165 inline 6

If it is that frozen, be prepared for at least a re-ring even if you get it running...might get lucky though. Patience is key in getting it to turn over. You do have all six plugs out, right? Soak the cylinders (I use PB Blaster) and let her sit....and sit...and maybe sit a little longer. You really need to get to the crank bolt. Mark the adjustment bolt, support the motor, and remove the front motor mount it you have to. A light duty impact can help also if you have room. It may take a few days (or never) to get it to turn. You may also want to pull the outdrive to verify that is not the culprit (you need a new impeller anyway). Once free, put a teaspoon of light oil in the cylinders and continue to turn by hand for a while. Then use the starter in twenty second bursts. Plugs still out. It would also help to pull the distributor and use a pre-oiler if you have one to take the initial wear off the bearings. Put it back together, and good luck. It's always worth a try, but you may find in the long run that a rebuild is in order. They are very simple engines to pull and rebuild.

 

[ziggy]

Re: Stuck 1970 Mercruiser 165 inline 6

i don't think the L6 has a harmonic balancer bolt.... least the two i've had didn't.... i've used a strap wrench on it to roll it over, but mine haven't been stuck... good idea on removing the drive to make sure that ain't the culprit...
i've never unstuck an engine before. but i've read marvel mystry oil works pretty good... no personal facts to convey though... good luck....

 

[curliss]

Re: Stuck 1970 Mercruiser 165 inline 6

Thanks for the good comments. I have been soaking the cylinders in PB Blaster for two days now. Not sure how stuck it is. I can't move it by hand or starter (with plugs out of course). I hope to get to work on it this weekend and will post progress - thanks again.

 

[Fishermark]

Re: Stuck 1970 Mercruiser 165 inline 6

I agree that you definitely want to get the outdrive off. It needs to come off and do some maintenance and checking of various items anyway.

The idea of pre-oiling is a good one... but I believe you will have trouble finding a tool that will fit and block off the oil passages that the distributor normally does. The tool used for Chevy V8s will not fit. You can still turn the oil pump with a drill and long straight extension... but would not be as effective as using the proper tool.

 

[curliss]

Re: Stuck 1970 Mercruiser 165 inline 6

OK - Are you saying you can turn the oil pump through the distributer hole? I have never even considered this. How do you go about that? You mentioned a drill/extension - what kind of fitting is down on the oil pump that you turn? what direction do you spin it? Thanks.

 

[Silvertip]

Re: Stuck 1970 Mercruiser 165 inline 6

Look at the bottom of the distributor drive gear. That tells you what you need to spin the oil pump. As for turning the engine I would suggest you NOT use the starter unless you want to break the rings or a ring land on a piston. The procedure is to soak this engine and walk away for at least a week. Soak it again and walk away for another week. Now attempt to "rock" the engine (slight clockwise/counter clockwise). If you feel no movement at all, soak again and wait. Repeat this process until you get even the slightest movement. Then soak again for a day or two. Rock it back and forth. Each attempt will exhibit ever so slight additional movement until the engine is free. Now lube the cylinders and spin the engine with the starter. Install the distributor (make sure you get the timing right), install the plugs and fire it up. Keep in mind that if the cylinders were rusty, chances are the cam is too and may eat the lifters and/or cam lobes quickly so pay attention for relatively rapid power decreases.

 

[Fishermark]

Re: Stuck 1970 Mercruiser 165 inline 6

OK - Are you saying you can turn the oil pump through the distributer hole? I have never even considered this. How do you go about that? You mentioned a drill/extension - what kind of fitting is down on the oil pump that you turn? what direction do you spin it? Thanks.

This is what a typical priming tool looks like, but as I mention, it won't fit your engine, and it will be difficult to find one to fit your engine:

If you remove the distributor, you will see that the pump is simply slotted. Even a long flat bladed screw driver will reach down and turn the oil pump. If you cut it off and chucked it into your drill you could turn the pump - clockwise.... but without blocking the oil passages it would no very little good.

 

[taliesin1935]

Re: Stuck 1970 Mercruiser 165 inline 6

Was that the one in Weidman? I bid on that one. NICE looking rig. Even if you need a rebuild it's a sweet boat....worth it.

 

[fishmen111]

Re: Stuck 1970 Mercruiser 165 inline 6

It is easy to make one cheap. Go to a junk yard and grab a distributor from a 250 straight six (many late 70, early 80s Chevy vans and pu had these). Grind off the cam drive gear at the bottom and then I drill a hole in the top of the shaft (cap removed, of coursr) large enough to hammer a six sided Phillips bit into the hole. Connect your drill and pump away.

 

[chiefalen]

Re: Stuck 1970 Mercruiser 165 inline 6

I'm all for trying to un-stick a motor thats can be freed with pb blaster.

However, to do it right, it needs to be pulled, the head off, turned over after drained.

Oil inspected, than pan pulled, then you in business.

Then you will know how the pan looks, how everything looks.

I didn't even get to the risers and manifold.

Everything has to be eyeballed.

Do it now or do it latter.

But your gonna be doing it.

Don s jeez he so smart, "Why is there no time to do it right the first time", or something like that.

Heres the whole quote: "Why is there never enough time to do it right the first time, But always enough time to do it again?"

I came back twice to get it right.

 

[curliss]

Re: Stuck 1970 Mercruiser 165 inline 6

Was that the one in Weidman? I bid on that one. NICE looking rig. Even if you need a rebuild it's a sweet boat....worth it.

Taliesin1935 - This one was in Michigan near Mout Pleasant. It is in fantastic shape (with the exception of the still stuck engine) The deal even included two electric Big Jon downriggers!

Regarding the stuck engine - I've been super busy at work and haven't had much time to work on the boat. I've pulled the outdrive (with difficulty) and there was water in the bellows so the U-joint is a little rusty, and the gimbal is corroded frozen. So that has to come out and a whole transom reseal kit -

I've been soaking the engine periodically with PB Blaster - so far no movement, but I can only apply torque by hand, i.e. not much since there's no way I can see to get any leverage without removing the front mount.

I was sure hoping this would be easy... I should have some more time to work on it this weekend.

Also - the oil looks good, what I can see of the lifters it all looks good and oiled without milky oil or corrosion, or gunk.

To stay in good graces with the wife I'd like to get this running right with minimal expenditure. Can anyone comment if it is possible to do a ring job (figuring I'll need that) without a complete rebuild? I was also thinking about get a the head redone since it is pretty cheap, and would remove that worry. I can get a remanufactured marine head for $128 and a complete reman marine engine for $1400 delivered. I'm just not sure what the best use of my time and money is at this point to get a good running reliable powerplant.

 

[Fishermark]

Re: Stuck 1970 Mercruiser 165 inline 6

That's a very easy engine to work on and rebuild. Here's a link showing what I did on a similiar engine:
http://forums.iboats.com/showthread.php?t=230711

 

[chiefalen]

Re: Stuck 1970 Mercruiser 165 inline 6

I did a nova 250.

Inline six same as the inline six merc used.

I just loved working on that motor.

Yanked it out and had it in my fathers garage.

Brought it over to a machine shop.

My friends father was a electrician, and wired the machine shop and the guy who owned the machine shop wanted just to teach us about motors and didn't charge me a cent.

They bored it out and g-d it was fast. That guy was good. And everything i had to buy we got at his price. Half the stuff was laying around.

Some of it he charged to customers.

Took all summer. But finally had it back together.

Back then everyone was working on novas, parts were easy to get.

Gave it to my sister when i got married.

She wrapped it around a pole.

 

[curliss]

Re: Stuck 1970 Mercruiser 165 inline 6

UPDATE - OK, after multiple soakings in PB Blaster the engine would not free up with what little torque I could get on the harmonic balancer in front. I decided to pull the engine - as that would let me address other issues easily as well. When I put a wrench on the first drive coupler nut the engine rotated pretty easily! After getting the coupler off and the engine on a stand I discovered that the starter was shot. After changing the oil and rotating the engine by hand several times I put in a rebuilt starter and did a cold cranking compression check. I got 155-155-150-155-160-155. This seems to be pretty healthy to me, and now I'm thinking I'll just do all the normal maintenance items and put the engine back in. Any thoughts on this plan?

Also - Another question. When pulling the motor there was a set of two wires (purple and blue) that ran into the top area of the transom plate. The wire insulation was broken and the wires were corroded near the disconnect plugs. Any idea what these are?? I can't find a reference to them anywhere. If they're easy to replace I will, otherwise thinking I'll cut them back to good wire and spice in new ends.

 

[curliss]

Re: Stuck 1970 Mercruiser 165 inline 6

What checks should be done on the head? I am going to torque the head bolts - anything else?

 

[chiefalen]

Re: Stuck 1970 Mercruiser 165 inline 6

Trim indicator sender wires to the gauge on the dash.

Make sure the mating surfaces are true on the head and stick it back on with a new head gasket.

Manifold good, riser good, no flapper stuck in the exhaust pipe ?

Make sure the t-stat new one.

The oil pan good, lip good, timing cover good, lower lip on timing cover good.

Paint the heck out of everything, pan 3-4 times after you clean it real, real, good.

Check the points, wires, plugs gaped right.

Clean the neg ground good, connections good with the battery disconnected.

Good battery cables, and good battery fully charged.

Check the coupler good.

Make sure there is water going to the drive when you start it.

Good luck !

 

[curliss]

Re: Stuck 1970 Mercruiser 165 inline 6

Where in the exhaust system should the flapper valve be? I looked, but couldn't see one - maybe removed at some point? Also - I don't think this model (1970) has trim indicator senders in the outdrive - I believe it uses the transom mounted part that looks like a small cylinder about 4 inches long. The purple and blue wires come right out of the transom plate a few inches above where the water pipe comes through.

 

[Bondo]

Re: Stuck 1970 Mercruiser 165 inline 6

Ayuh,....


Complete with pictures,... The explanations are found Here....

 

[curliss]

Re: Stuck 1970 Mercruiser 165 inline 6

Thanks Bond-o,

Wish I'd known about those archived manuals a few weeks ago... Invaluable.