87 ford 2.3l OMC cranks to TDC and stops

Mgsissonvt

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Newbie here, both on the forum and working on boats. I've done plenty of work on vehicles and know my way around decently.

Here is the scenario with way more information than anyone should need. I know this is not a coveted boat but it came with the trailer I bought and I'd like to get it running. The boat has not been run for a couple of years. The last owner said the timing belt had broken and they could never get it figured out after that.

Motor: 1987 2.3l ford OMC cobra i/o. I tried to specify everywhere but I've only been putting marine parts on this boat.

Here is what I have done.
1. Installed new marine timing belt: Lined up the cam/crank at TDC and verified by removing the #1 and #4 plug that they were both at TDC. There were no marks on the oil slinger wheel and somewhere on here I saw that it's position is irrelevant. After installing I rotated 720 degrees and everything was aligned properly.

2. Set the Distributor to fire on #1 at TDC on #1 cylinder. (I noticed the position is not the same as some of the factory pictures, but it should fire #1 at TDC and also is in the correct firing order). The distributor was moved and re-positioned to get it lined up right.

3. Removed and cleaned the carb, although it did not look bad at all.

4.Tried to start the motor. It turned over but very very slowly. Turned over 3-5 times with no issues.

5.Identified that there was no fuel getting sucked into the carb via the fuel pump. Removed the fuel pump, cleaned and replaced the gasket and re-installed. I'm using an auxiliary fuel tank with good fuel and a line run into the fuel separator.

6. Tried to start the motor. It turned over slowly. Turned over 3 times with no issues.

7. Replaced the battery, marine starter (BTW you CAN order marine starters for this boat form O'Reilly's auto parts, the manufacturer is Wilson and they are 100% match of factory marine), replaced ground and hot connections after reading on the forum that those could cause the sluggish turn-over. I was hoping that maybe the pump wasn't getting hit enough to actually pull fuel.

8. Tried to start the motor. It turned over like a brand new motor, quick and it honestly sounded great at least 3 or 4 revolutions.

9. Before reconnecting all of the fuel lines I poured a little fuel into the carb to see if i could get it to fire. Tried to start the motor and it was maybe two revolutions and then a hard clunk.

Now the motor will turn by hand to TDC on the #1 and #4 and then its like it hit a wall. I can reverse it back to TDC on #1 and #4 and it stops again. I can't imagine that it was any of the parts that were added/removed because it was turning over fine. We have removed the starter, fuel pump and it still hits the wall. We removed all 4 plugs, no water, turned the motor by hand and watched with a light scope and each of the cylinders are moving properly and look good. I removed the parts that I installed and we still have the same issue. I have no idea what could be causing this. I had a similar experience in a 4runner once where it has been left in gear so I verified that I'm in neutral and can spin the prop. Any ideas would be greatly appreciated.

I'm wondering about the oil slinger wheel or the distributor positioning. Could either of these cause the issues we are seeing.

Thanks in advance.

Matt
 

tpenfield

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Take the spark plugs out and try to crank it with the starter.
 

Mgsissonvt

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Update: I removed the distributor and it still hangs, i also tore down to the timing belt and it still appears to be aligned properly just stops shy of TDC.

Wouldn't starting it with the starter risk damaging more if something isn't allowing it to turn? I can certainly put it back together in 45 minutes and give that a try.
 

tpenfield

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If you are concerned about some damage . . . take the spark plugs out and turn the engine over a few turns with a breaker bar.
 

Mgsissonvt

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I assumed you meant to try to use the starter to break through whatever was keeping it from turning. The spark plugs have been out and it will still only turn 180 degrees before hitting a dead stop.

"We removed all 4 plugs, no water, turned the motor by hand and watched with a light scope and each of the cylinders are moving properly and look good"

We watched #1 and #4 approach top dead center through the spark plug hole with a lighted digital scope, they aren't hitting anything.

Any other ideas?
 

GA_Boater

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Are #1 & #4 at TCD on the exhaust stroke and not on the compression stroke? The timing belt may 180 degrees out.
 

GA_Boater

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TDC is usually the compression stroke . . .

True, but looking at the piston at TDC is the same as when on the exhaust stroke. The valves need to be looked at to see that they are both closed.
 

Speak

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Pull the valve cover off and take a look at the rocker arms. Sounds like something is jamming in the head. The motor is a non interference fit so a valve should not be able to hit a piston unless it's dropped into the cylinder. That leaves either a rod that is jamming up or a rocker arm that had come away from the cam jamming that up. Just my 2 cents since I gave muddled around with these engines in the past / good luck
 

Mgsissonvt

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Thanks for the ideas. I already removed the bolts for the valve cover earlier but was having some issues getting it off. I'm letting it soak a bit and will pull it off in the morning.

It just seems really odd to me that it would turn over consistently until I got a starter on it that could actually turn it over quickly. I can confirm nothing has fallen down into the cylinders. I would assume a broken rod, or stuck rod would be indicated by the piston not moving properly. It looks like they are moving up and down correctly with #1 and #4 and then #2 and #3 at TDC at the same time.

What would be the indicator of compression stroke or exhaust stroke with the valve cover off? Closed valve on #1 and open on #4 would mean compression for #1 and exhaust for #4?
 

GA_Boater

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TDC is when #1 is at the top of cylinder and both valves are closed.
 

tpenfield

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True, but looking at the piston at TDC is the same as when on the exhaust stroke. The valves need to be looked at to see that they are both closed.

Yes, my bad . . . doing too many things at once :)
 

G_Hipster

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True, but looking at the piston at TDC is the same as when on the exhaust stroke. The valves need to be looked at to see that they are both closed.


X's 2 Me thinks the 4 stroke principles were missed from the get go.

To the op, Rap that cover with a rubber mallet, and get a look. Dot to dot doesn't always put an engine on it's compression stroke. I always verify with a finger over the hole for pressure and bring the balancer to zero. Then rock it back and forth to verify that I'm at tdc and the balancer hasn't slipped. Then drop the dist. and wire the cap according to manual. If your only getting 180 degrees rotation and not almost 360(tdc to almost tdc) Loose/cracked rod cap, cracked piston etc.
 
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Mgsissonvt

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I pulled the valve cover off and confirmed that at TDC #1 is closed.

I did however find three stuck valves and I'm guessing there is my issue. Would a stuck valve keep the camshaft from turning or would it just break the rocker arm or other.
 

Mgsissonvt

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I should clarify that this is a little above my knowledge of engines. Please forgive my descriptions but I think you all will get the idea.

For each cylinder there are two "eggs" on the camshaft. Those eggs rotate and press on the rocker arms that push open the valves. One side of the rocker is on a spring, the other side just looks like a rod with a gasket on it. The rod side of three of the valves doesn't move when i tap it with a rubber mallet. I can move the others at least a little with my hand.

Any recommendations on trying to fix these without pulling the head? I assume I can remove the cam, put some diesel or wd40 on them and tap with a rubber mallet until they break free?
 

GA_Boater

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I pulled the valve cover off and confirmed that at TDC #1 is closed.

I did however find three stuck valves and I'm guessing there is my issue. Would a stuck valve keep the camshaft from turning or would it just break the rocker arm or other.

Yes it can stop the motor from turning and maybe break a rocker or the timing belt.
 

Mgsissonvt

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Another update. After turning the engine by hand as far as I can I figured out that there is really only one valve rod that is potentially stuck, but honestly I think if I could turn the cam a little more it wouldn't feel that way. So I don't think that is the issue.

I've got a picture of the #1 cylinder with the crank/cam almost at TDC (as far as it will go which is maybe 5 teeth shy on the cam). I assume with the "eggs" to either side, and no pressure on the valves is closed. Please let me know if that is incorrect.

Thanks,

Matt
 

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Speak

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I had the same problem on my 2.3L. Turned out in the end my head was cracked and was putting weird pressure on the cam causing it to bind during rotation. You could remove the t belt and the cam from the head allowing the valves to close. If the motor turns over now you know it's all in the head. Just a thought. I think u will be pulling the head soon
 

Mgsissonvt

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Good thinking. I figured I could eliminate more by removing the timing belt again so I did that a little while ago. I am able to turn the cam over now with a wrench and although it does seem to jump between each turn, it does rotate freely.

The crank on the other hand turns the same amount and stops. Timing belt, Plugs, distributor, fuel pump, starter are all removed and I have the same issue but eliminated the cam as the issue. Could it be something with the outboard? I can still spin the prop freely but I'm wondering if something is seized there keeping the crank from turning.

Otherwise it is bad news for this engine. On a happy note, there may be some hard to find 2.3l OMC parts coming up for sale here soon....
 

Lou C

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If the outdrive is locked up then for sure you'd have trouble turning the engine. It is not hard to remove, shift in neutral, find something to support it and there are 6 nuts that bolt it to the transom mount. That and removing the rod that goes through the trim rams, it should slide off.

Are you sure that when you installed the timing belt, that the crankshaft camshaft and auxillary shaft (that drives the distributor) were in the proper position relative to each other? In my OMC shop manual for that engine, the crankshaft sprocket has a dot on it that is supposed to be aligned with a notch on a bracket that is just above and to the right of the sprocket. The cam shaft is supposed to be aligned by lining up the timing mark on it with a grid that is on the cyl head. Then you are supposed to line up the auxillary shaft so that distributor rotor is pointing at #1 cyl terminal. This is very basic but there are these three steps that must be followed to have the crankshaft, camshaft and aux shaft (that drives the distributor) in proper phase with each other. Unlike many other engines, on the Ford OHC the distributor is not driven directly off the camshaft gear but rather by an auxillary shaft that is turned by a sprocket just like the camshaft.
 
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