Water in cylinder 1988 90hp Johnson

[jdupree]

This motor had a complete power head rebuild back in May. The power pack was just replaced about 1 month ago and spark plug wires were replaced. The coils were not. Motor seems to run good and has plenty of power. Noticed that when I changed the plugs the plug on the lower port cylinder was very clean and appeared to have moisture in it.

Compression is around 120psi cold and 100 at warm operating temp. I have noticed that when running around 4000rpm's that every now and then it might drop to 3800 for a second and then pick back up. Does it sound like an ignition issue in that cylinder? Thanks for the advice in advance.

 

[Dhadley]

Re: Water in cylinder 1988 90hp Johnson

Moisture on a spark plug is never good. That means there could be water in the steel sleeve and on the steel rod and the steel crank and the steel bearings.......well, you get the drift. Pop the head off and see if the gasket is still OK.

 

[jdupree]

Re: Water in cylinder 1988 90hp Johnson

Thanks,

If the head gasket checks out what do I need to check?

 

[emdsapmgr]

Re: Water in cylinder 1988 90hp Johnson

While unlikely, possible you have a crack in the inner exhaust cover, or casting porosity-pumping water into the exhaust cavity. Hold the cover level and put some water on the backside-see if it leaks through.

 

[jdupree]

Re: Water in cylinder 1988 90hp Johnson (v-4)

Re: Water in cylinder 1988 90hp Johnson (v-4)

Once I pull the head, when I put the head gasket back on do I need to use a sealer of any type or just put the gasket on? Could you also tell me the torque specs for that motor.

When I torque it down is there a specific order or just torque it down evenly maybe starting from top to bottom and so on? Thanks alot!

 

[mikesea]

Re: Water in cylinder 1988 90hp Johnson

Since you mention water in the cyl.Here's a common v-4 crossflow omc problem.There are water passages that run whithin the exhust .Behind the large plate,on the rear of the engine(inside)at the bottom ,outside the exhust ports for the cyl,there are triangular casts,those cast warp,causing minute cracks,that allow water seepage into the exhust ports.If it's not a leaking gasket from the rebuild,(hopefully it is)I suspect the water leak in the exhust.I worked for a powerhead guy,and we needed to weld MANY MANY.

 

[jdupree]

Re: Water in cylinder 1988 90hp Johnson

Thanks for the info. I will check that out.

 

[jdupree]

Re: Water in cylinder 1988 90hp Johnson

Update:

Pulled the head on the starboard side. Found that I do have water instrusion on the bottom cylinder. Looked like to me that the guy who re-built the motor did not machine the head to clean off old gasket. The cylinder wall looks good and is smooth with no grooves.

Did notice that on the top cylinder that I have one place where the cylinder wall has a little groove in it big enough to catch your fingernail. Rest of the wall looks good and is smooth. Is this something I need to be concerned with or might have been a piece of debris?

 

[mikesea]

Re: Water in cylinder 1988 90hp Johnson

You might want to get a piece of 80 grit emery or the like and a piece of marble wide enough to use as a backing to run over the deck of the cyl head and block,try doing a figure 8,it will be hard on the block,look to see any uneveness,the head will show a nice pattern except for where there might be a warp

 

[jdupree]

Re: Water in cylinder 1988 90hp Johnson

Update and need help!

Just sealed up the new head gaskets! Cylinder walls looked good before I sealed it up. I guess it should with around 30 hrs since re-build. Cranked it up and it fired right up! Let it run about 5 minutes and it ran great. The motor runs cool at about 125deg. Pulled the plugs after it ran for the 5 minutes. The #4 plug was dry as a bone? No oil or water or anything was on the plug? The rest of the plugs had a little oil on them.

The only reason that I pulled the head to start with is that when I changed the plugs the #4 plug was very clean with a little water on it. Motor ran great prior to that and I would have never noticed If I had not pulled the plug.

As I stated above the #4 cylinder looked good with no scaring or scratches.

Is it possible that I am still getting water in that cylinder? When the motor was rebuilt back in May the block was bored and no problems were found. Is it safe to run this motor? I checked the #4 cylinder temp while it was runnign and it was 125deg. Is it safe to run this motor? Please help with some suggstions. Thanks!

 

[mikesea]

Re: Water in cylinder 1988 90hp Johnson

Sorry,but I'm confused.If the motor ran great,for 5min,why were you concerned.I understand you say the #4 SEEMS to be clean of fuel,oil,and water,if it wasn't getting fuel,it wouldnt run great,if it was getting water,it certainly wouldnt run great and probably would have a bit of rust. I understand your apprehension.Take it for a ride,let it warm up,and thendecide if its running great. If it is,you fixed the problem which was probably abad head gasket.If you have spark,compression and fuel,it should idle good and get you your top end rpm.Of course if water is there ,it wont happen. But I guess the real test is in the sea trial. Good luck,at first hint of trouble shut it down and go from there.You might have water in your fuel and it got past the carbs when you first noticed the prob. How is your fuel water seperator if you have one or does your filter show water,drain the bottom carb and collect the fuel,let it sit ina jar and see if there is water.You may NOT have a problem at all.

 

[jdupree]

Re: Water in cylinder 1988 90hp Johnson

I guess you are right. Need to put it in the water and run it. Right before I pulled the head and found water in the #4 cylinder, I did notice when I tried to come up on plane it acted like it was missing a cylinder and lacked some power. I backed it off and tried it again and it came up on plane then. Must have been the water in the #4.

I plan to run it this week. I guess I will find out once I run it around 4000 rpm's to see what it will do. Just replaced my water/fuel seperator last month and I also have a brand new aluminum tank. It just really concerns me how dry the #4 plug was today. Thanks for the help and I will keep you posted.

John

 

[Solittle]

Re: Water in cylinder 1988 90hp Johnson

How long was the warranty on the rebuild?

 

[mikesea]

Re: Water in cylinder 1988 90hp Johnson

John,I got your PM .did you get my reply.I'm hoping I'm sending them right.I'm trying to figure out if you sent the Pm before or after your last running of the eng,

 

[jdupree]

Re: Water in cylinder 1988 90hp Johnson

John,I got your PM .did you get my reply.I'm hoping I'm sending them right.I'm trying to figure out if you sent the Pm before or after your last running of the eng,

Don't think that I received it, but I am not sure how to check it.

I let the motor run for 20 minutes in the yard on Sunday afternoon. Ran great and the #4 cylinder never got hotter that 125deg. - so it is being lubricated. Started to see signs of just a little oil on the #4 plug but not much.

I guess I will know more once sea trial it and then pull that plug.

 

[funpilot]

Re: Water in cylinder 1988 90hp Johnson

You might have had two problems, the head gasket and flatness of the cylinder head, and the lower carb might be lean on one side. The two barrel carbs are essentially two carbs which share a common fuel bowl. I would consider cleaning the carbs, including soaking them, if my compression was even, but my spark plugs were fouling unevenly.

fp

 

[jdupree]

Re: Water in cylinder 1988 90hp Johnson

You might have had two problems, the head gasket and flatness of the cylinder head, and the lower carb might be lean on one side. The two barrel carbs are essentially two carbs which share a common fuel bowl. I would consider cleaning the carbs, including soaking them, if my compression was even, but my spark plugs were fouling unevenly.

fp

Thanks for the info. I just re-built the carbs from head to toe about 2 months ago. I have a brand new aluminum tank which has just been installed and a brand new water/fuel sep. If the #4 cylinder is running a little lean shouldn't that cylinder run hotter than the rest? When I pulled the head, the #4 cylinder looked great! It just had a little surface rust but very smooth.

I hope to run the boat later in the week. If it runs good, and doesn't get hot in that cylinder, I would say I am ok???????

 

[funpilot]

Re: Water in cylinder 1988 90hp Johnson

Did you soak and really clean out the carb passages, including removing the welch plugs?

The VRO should send the correct (same) oil/fuel mix to both carbs. Absent an electrical problem, three plugs running a touch oily and one plug running dry as a bone (tan, I assume, and not shiney, shiney would indicate water still getting into that cylinder) would indicate a carb problem, namely a plugged orifice on one side, or in other words, lean.

fp

 

[jdupree]

Re: Water in cylinder 1988 90hp Johnson

Did you soak and really clean out the carb passages, including removing the welch plugs?

The VRO should send the correct (same) oil/fuel mix to both carbs. Absent an electrical problem, three plugs running a touch oily and one plug running dry as a bone (tan, I assume, and not shiney, shiney would indicate water still getting into that cylinder) would indicate a carb problem, namely a plugged orifice on one side, or in other words, lean.

fp

I did remove the frost plugs and completely cleaned the carbs. Actually the carbs were really clean when I took them off. When the powerhead was re-built I disconnected the vro - so I am mixing.

It would sound like a lean condition to me as well on the #4 cylinder. What baffles me is that the #4 cylinder has not scared at all and never gets hot. The cylinder looks like it was just bored yesterday.

I have my temp gauge hooked directly to the #4 cylinder just as a precaution. If weather permits, I plan to go fishing on Friday. I will see how the motor does after several hours of running. I will then pull the plug and take a look. Thanks for all the input and I will post the results.

 

[emdsapmgr]

Re: Water in cylinder 1988 90hp Johnson

Your crossflow may seem to run fine on 3 cylinders. Unless you run it hard- under load, you may not know you actually are having a no-fire or misfire situation going on with #4. Running on the hose is not a good test. All 4 spark plugs need to look the same, or close to it. Get the boat up on plane and put a timing light on each plug wire. See what flashes you get. Should be strong and constant. Also, look for any chance the spark may be intermittent. Once you know the spark is good, then look to the fuel side. Make sure all three jets on #4 are clear of debris. I would not run the engine much till you know the source of the problem.