1989 OMC 2.3L A couple issues

[ccsears1981]

Just rebuilt my 2.3L and now I have a couple problems. First it will not idle below 1000 RPMs which I know isn't good for shifting. If I idle it down it wants to stall out. It also has a rough idle to it with a slight hesitation when I first throtle it. After the first throttle I can rev on it and it sounds perfect. Tried playing with the timing and adjusting the Carb, also to mention the carb was remanufactured by Natinal Carb so everything is new. Anyway carb adjusting and timing isn't changing the rought idle or the hesitation. I also changed to points out for the electronic ignition and made sure the pick-up wire for the distributor had a 12V feed from the ignition switch. I left the 6V wire attached to the coil and the ESA.
My second issue may be linked, I have quite a bit of steam / Water coming from the exhaust. Its more like water as I can place my hand by the exhuast and my hand is soaking wet. I have no water getting into the oil and the engine isn't overheating its running about 170 degrees. done a compression test and I have 150 on piston 1,2 and 4 and 120 on piston 3. Really don't think its a head gasket or cracked head as the compression is lower but still not bad compression either. May be due to a leaking valve. Checked the spark plugs and no signs of water on them and no signs of lean or rich fuel. New plugs and new wires also on it. Only thing still needs changed is water seperator but i pulled it and it doesn't show signs of water or dirt.
So is my idle problem related to water making its way into the combustion chamber somehow or do I have 2 things going on here. I also thought maybe the rough idle and hesitation may be because the disributor is being powered by a different source than the coil or the coil also needs 12v power, but affraid to try this so I don't burn the ESA. Any suggestions?

 

[HT32BSX115]

Re: 1989 OMC 2.3L A couple issues

First it will not idle below 1000 RPMs which I know isn't good for shifting. If I idle it down it wants to stall out. It also has a rough idle to it with a slight hesitation when I first throtle it. After the first throttle I can rev on it and it sounds perfect. Tried playing with the timing and adjusting the Carb, also to mention the carb was remanufactured by Natinal Carb so everything is new. Anyway carb adjusting and timing isn't changing the rought idle or the hesitation.

Howdy,

You need to fix that high idle! It will damage your drive if you continue using the drive with an idle speed higher than recommended. You might have the timing wrong, possibly a vacuum leak and that carb may still be screwed up. Just because it was "rebuilt" doesn't mean it was done "right".

My second issue may be linked, I have quite a bit of steam / Water coming from the exhaust. Its more like water as I can place my hand by the exhuast and my hand is soaking wet. I have no water getting into the oil and the engine isn't overheating its running about 170 degrees. done a compression test and I have 150 on piston 1,2 and 4 and 120 on piston 3. Really don't think its a head gasket or cracked head as the compression is lower but still not bad compression either.

Water coming out of the exhaust is normal. That's where it exits the cooling system. It can come from nowhere else.

If the engine hydrolocks after you shut it down, you might have either a cracked exhaust manifold, riser or a leaking riser gasket.........but once you get it running, even a leaking exhaust manifold or riser won't "hurt" anything (until you shut it down). pulling plugs will reveal water in cyls if you crank it.


Cheers,

Rick

 

[Howard Sterndrive]

Re: 1989 OMC 2.3L A couple issues

I think you need to slow down and just focus on your water leak first. Get a mirror in there and find it. A wet cloud of water/exhaust being sucked into the air intake will definitely affect performance.

30 psi lower compression on one cylinder is a cause for concern. You want to try adjusting the valves before panicking though.

Has the timing belt ever been changed? Maybe it jumped a tooth. Easy to do a visual inspection of the belt.

 

[Howard Sterndrive]

Re: 1989 OMC 2.3L A couple issues

Water coming out of the exhaust is normal. That's where it exits the cooling system. It can come from nowhere else.

I was assuming he meant inside the bilge area, but I probably shouldn't assume anything

I also missed the just rebuilt thing somehow...duh... I'll go back to assuming: the timing belt is on right and new now?

 

[HT32BSX115]

Re: 1989 OMC 2.3L A couple issues

but I probably shouldn't assume anything

I'm with you there! Been there done that etc!

 

[ccsears1981]

Re: 1989 OMC 2.3L A couple issues

So my worst fear has been confirmed tonight, i pulled the plugs again to re-check compression and now I see water in the number 2 piston. Now here is my new question as I am confident this is whats giving me my idle issue also now. I still done a compression check and its still hitting 150 and holding when I let it sit for awhile also when I loosen the drain **** under the exhaust manifold only air came out, no water so is it possible that the water is going into the combustion chamber through the exhaust manifold? I would like to find out before pulling the head back off and sending it off again to be checked for cracks. It was suppose to been checked last month when I send it in to get re-surfaced.

 

[HT32BSX115]

Re: 1989 OMC 2.3L A couple issues

is it possible that the water is going into the combustion chamber through the exhaust manifold? I would like to find out before pulling the head back off and sending it off again to be checked for cracks. It was suppose to been checked last month when I send it in to get re-surfaced.

Well, If you think about it, you have good compression. so your head gasket is likely holding. When you shut the engine down one cyl usually has an open exhaust valve. If there's ANY water in the exhaust manifold, it'll run right into that open exhaust valve.

You might have a cracked riser, cracked exhaust manifold or leaking riser gasket.

If you want to check for cooling system leaks from cracks etc, pressure check the cooling system BEFORE you pull the head.

 

[ccsears1981]

Re: 1989 OMC 2.3L A couple issues

So how exactly do I pressure check the cooling system? I assume i would pull the inlet hose coming from the transom and apply air but how much and is there anything I need to unhook first? I am trying to figure out how its just one cylinder filling with water if its coming from the manifold or riser. wouldnt it be letting water in all the cylinders?

 

[ccsears1981]

Re: 1989 OMC 2.3L A couple issues

So I pulled the manifold off the engine, it appears to be nice and solid, not sure how to pressure test it but I don't think its cracked. the riser looks good also, the gasket was pretty old so I am hoping this is the problem I will replace the gasket today and put it back together. I did a pressure test on the cylinder and here are the results. The compression test this time was only hitting 90 PSI for the dry test, done a wet test and brought it up to 130 PSI also sprayed some cleaner in the exhaust valve thinking it might be sticking. Done a pressure test and there is air coming from the exhaust valve, good news is I left the u host on the block that goes to the t-stat and I can see the water left in the block. Sealed off the exhaust port to see if air was leaking anywhere else and everything looked good, no air bubbles coming from the water so here is my theory.

Water coming in from the riser gasket, exhaust valve sticking so it sucked in the water from the manifold during the intake stroke and the reason for the good compression earlier and weak now is the cylinder had water to seal the rings and now the weak compression is coming from the rings not fully seated. given that its new rings and a fresh rebuild if I had water getting in from the beginning the piston just didn't get hot enough to set the rings like the other 3 cylinders which are hitting at 150 PSI. This is my theory any thoughts or opinions? I will post back later tonight with the results of the riser gasket. If this isn't it then no other option but having a bad head or head gasket just didn't seat right from the rebuild.

 

[HT32BSX115]

Re: 1989 OMC 2.3L A couple issues

So how exactly do I pressure check the cooling system? I assume i would pull the inlet hose coming from the transom and apply air but how much and is there anything I need to unhook first? I am trying to figure out how its just one cylinder filling with water if its coming from the manifold or riser. wouldnt it be letting water in all the cylinders?

After you remove the manifold, think of your engine as an air tank that has several openings.

To pressure check it, you connect a gage to one of them, a valve and air hose to another and block the rest of them.

Pump the engine up to about 15 psi and close the valve. The gage pressure should not drop. If it does, you have a leak.


If it's external you can used soapy water and look for bubbles. If it's internal, you'll hear it in the oil fill tube etc.....


You cannot pressure test the manifold or riser or test the riser gasket using the above pressure test... You must inspect them (replace the gaskets)

There is a way to test the manifold using acetone. I think the technique is in the "sticky" messages at the top of the forum.

 

[ccsears1981]

Re: 1989 OMC 2.3L A couple issues

Didnt pressure test cooling system but did the cylinder as in my last post, whats your thoughts on my theory?

 

[HT32BSX115]

Re: 1989 OMC 2.3L A couple issues

Didnt pressure test cooling system but did the cylinder as in my last post, whats your thoughts on my theory?

compression tests will tell you if you have ring, valve and maybe other head problems like head gaskets, cracked head etc.

It will not tell you if your cooling system is leaking.

Water in one cyl of a marine engine (with jacketed manifolds/risers) with good compression, is usually a leaking manifold/riser or assoc gasket.

 

[ccsears1981]

Re: 1989 OMC 2.3L A couple issues

Right, I understand that. But not only did I do the compression test, I also made my own leak down tester and pushed 100 PSI into the cylinders. With the manifold off I left the u hose connected to teh block that comes from the t-stat so I could see the water sitting in the hose which was left in the block. If the cooling system was leaking any at all I should have been able to see bubbles come out from the hose and hear the air. I didn't pressure the cooling system but wouldn't this be the next best thing. If 15 PSI is going to leak into the block 100 PSI should leak out.

 

[ccsears1981]

Re: 1989 OMC 2.3L A couple issues

Well I see now why you was so determine on the pressure check on the cooling system. Turned out it was the head gasket the blew on a water jacket. Its funny, I pressured the cylinder with 100 PSI and no leaks throught the cooling system pressure the cooling system with 15 PSI and it leaks into the combustion chamber. Hopefully it was just a bad cheap gasket in the rebuild kit put a felpro on last I am gonna go off if the machine shop didn't get the block or the head resurfaced right. Thanks for all the helpfull info HT!!! I worked on cars all my life and this experiment has taught me alot about the marine engine. Not as easy as I thought it would be.

 

[HT32BSX115]

Re: 1989 OMC 2.3L A couple issues

Well I see now why you was so determine on the pressure check on the cooling system. Turned out it was the head gasket the blew on a water jacket. Its funny, I pressured the cylinder with 100 PSI and no leaks throught the cooling system pressure the cooling system with 15 PSI and it leaks into the combustion chamber. Hopefully it was just a bad cheap gasket in the rebuild kit put a felpro on last I am gonna go off if the machine shop didn't get the block or the head resurfaced right. Thanks for all the helpfull info HT!!! I worked on cars all my life and this experiment has taught me alot about the marine engine. Not as easy as I thought it would be.

Well, marine engines really ARE as "easy" auto engines. You just have to look closer at some other things....

You may still have a riser/manifold leak/problem because a small amount of water in a cyl can cause you to "blow" a head gasket so don't ignore them.

leaking ex manifolds/risers are frequently the cause of OTHER problems down the road...... "Been there done that"

Cheers,


Rick