Take a look at my plugs and tell me what you think - 1989 Evinrude 175

[guitman32]

Motor is an '89 Evinrude 175 crossflow...took a trip to the keys this weekend, ran about 45 gallons (premium only) through her (a good bit of running for the old gal). She ran great spare noticing a decrease in idle stability (will die when throttling down to neutral; and when sitting at idle she will die more than occasionally, though only when in slow idle - i.e. motor warmed up) and an increase in white smoke (my brother even mentioned it unprovoked). Also noticed she is harder to start when cold than normal. Every time she dies on idle I touch the key and she comes right back to life. I have noticed these symptoms since the last two times Ive had her out including this last trip.

FWIW entire ignition system and all wiring/rigging is new. Before these issues, she idled strong for days and had no problems (had estimated 25 hrs on her completely issue free since the new ignition system and rigging).

Last I checked compression it was a somewhat even 85-95 on all cylinders (IIRC this cylinder had the lowest value at about 85).

Drove home Sunday evening, ran her on the muffs for 10 mins, then returned the next morning to do some investigating.

All plugs looked normal except for the lowest port cylinder.

Here is what I found on the plug in the lowest port cylinder:

1. Freshly pulled:

2. Wiped clean:

3. Plugs re-inserted and motor was run for 5 mins, pulled the plug again, same thing:

My guess is its water coming from a leak in the head gasket. I didn't have my compression tester with me today so I'm going to check that tomorrow.

What are your thoughts?

 

[emdsapmgr]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

Agree, that plug does not look normal. It looks milky, like you have some water intrustion in that cyl. You can get water in a cyl from a bad head gasket. Probably the easy thing to change at this point. If that does not do the trick, you need to look to the exhaust manifolds. Typically exhaust manifold leaks tend to affect the bottom cylinder first. You can have two issues with those manifolds: if they are old, they can lose their torque over time. Sometimes a retorque can help. Problem is that you can't get the inside bolts without removing the outer exhaust cover. Also, I've seen porosity in the casting of the inner manifold. If you pull the inner manifold, you can do a water check on the manifold, and a visual-with a light behind the manifold. A leaker is easlily fixed by aluminum welding. Once removed-reinstalling that exhaust system is not a simple task-check out the factory manual for alignment instructions.

 

[boobie]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

Is that water or metal flakes? Can't tell from pics.

 

[guitman32]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

Agree, that plug does not look normal. It looks milky, like you have some water intrustion in that cyl. You can get water in a cyl from a bad head gasket. Probably the easy thing to change at this point. If that does not do the trick, you need to look to the exhaust manifolds. Typically exhaust manifold leaks tend to affect the bottom cylinder first. You can have two issues with those manifolds: if they are old, they can lose their torque over time. Sometimes a retorque can help. Problem is that you can't get the inside bolts without removing the outer exhaust cover. Also, I've seen porosity in the casting of the inner manifold. If you pull the inner manifold, you can do a water check on the manifold, and a visual-with a light behind the manifold. A leaker is easlily fixed by aluminum welding. Once removed-reinstalling that exhaust system is not a simple task-check out the factory manual for alignment instructions.

Thanks for the advice...I plan to check the head gasket, run her, and if no improvement tackle the exhaust gasket. Hopefully I can avoid having to call in a welder...

Is that water or metal flakes? Can't tell from pics.

It was a combination of milky looking water and some residue of some sort. Almost looked like rust, which scares me.

Does that indicate anything in particular?

 

[1946Zephyr]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

I would take a compression test first, to see if the head gaskets are leaking.

 

[Mas]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

The rust is obviously from water inside the cylinder...head gasket/exhaust cover. Seems to have been sitting in there a while to be rusty. Is this a fresh or salty motor?

Mas

 

[guitman32]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

The rust is obviously from water inside the cylinder...head gasket/exhaust cover. Seems to have been sitting in there a while to be rusty. Is this a fresh or salty motor?

Mas

Thanks for the reply....its a salty motor without a doubt, but it hasn't been sitting around. Ive been running her quite regularly for the last 5-6 months. I ran 45 gals through her the day before I discovered the wet plug.

I figured the rust was from the water, but let me ask you this. When you get water in a cylinder, isn't the cylinder usually clean in appearance from the water "washing" the piston? I ask because the piston inside the cylinder looks far from clean. Actually, I would say it looks dirtier than the other pistons.

A storm decided to roll through South Fl today, so Ive had to postpone further diagnosis and examination. Hopefully the rain will clean by tomorrow morning.

 

[1946Zephyr]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

A compression test would be a good place to start. If your compression is good, them it's a safe bet that the exhaust cover is the culprit. If you let the motor sit too long and wait for the weather to clear, then it's likely more internal damage will occur. Sorry to say it.

 

[guitman32]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

A compression test would be a good place to start. If your compression is good, them it's a safe bet that the exhaust cover is the culprit. If you let the motor sit too long and wait for the weather to clear, then it's likely more internal damage will occur. Sorry to say it.

Noted. I have the same fear myself. I plan to tackle it tomorrow morning barring another storm.

Thanks for the idea re: compression..it will point me in the correct direction.

 

[guitman32]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

Well interesting update. Compression is an impressively even 100 on all cylinders. The improving compression is a trend that I have been noticing on this motor...the more I run her, the better (mainly more even) it gets.

She started on the third try today, no choke. Started with the rough idle initially, but once warmed up she idled like a top. I soaked the bolts today (they look like they've been removed before, look fresh) in prep for removing the cover.

Can anyone help me understand how a bad exhaust cover gasket can lead to water intrusion in the cylinder, while having great compression at the same time?

 

[Mas]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

The exhaust cover has an inner baffle...inside the baffle is where exhaust exits the cylinders. Between the baffle and cover, water circulates to cool the combustion gases by contact by creating a "cold inner baffle.". If the inner baffle is leaking due to a hole or other, water can be squirted by water pump pressure inside the exhaust ports into the cylinder...thus causing poor running and even rust if allowed to sit.

Mas

 

[guitman32]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

The exhaust cover has an inner baffle...inside the baffle is where exhaust exits the cylinders. Between the baffle and cover, water circulates to cool the combustion gases by contact by creating a "cold inner baffle.". If the inner baffle is leaking due to a hole or other, water can be squirted by water pump pressure inside the exhaust ports into the cylinder...thus causing poor running and even rust if allowed to sit.

Mas

Thanks for the explanation, much appreciated...it seems to make sense to me.

I want to be sure there is general consensus that I should pursue the exhaust gasket as opposed to the head gasket. Since the compression is even in the cylinder in question is that a red herring to be the exhaust gasket, or is there still a chance Im going to have to 'take a chance' on those head bolts (makes me nervous every time I look at them)?

 

[Mas]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

Any head bolt or exhaust cover bolt on a "salty motor" would make me nervous...especially the smaller exhaust cover screws. THey are easy to break...then what a pain and possible nightmare. If you do end up breaking a bolt/screw, do not use "easy outs"...take it to a machinist to have them removed properly without further damage.

MAybe some "pros" can chime in on their tricks to avoid breaking them in the first place.

Mas

 

[emdsapmgr]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

Have you noticed any issues with starting the engine? If enough water gets into a cyl, it can develop a hydraulic lock. A starting engine may turn over 3/4 turn, then slow or stop, then keep turning till it forces the excess water out the exhaust.

 

[guitman32]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

Have you noticed any issues with starting the engine? If enough water gets into a cyl, it can develop a hydraulic lock. A starting engine may turn over 3/4 turn, then slow or stop, then keep turning till it forces the excess water out the exhaust.

I can say with relative certainty that I haven't noticed any such resistance when starting.

When I mentioned I had trouble starting her in my original post, I was referring to the more-than-usual turns of the key it would take to get her to come to life...and the occurrence of what sounded like a single backfire (or some sort of loud firecracker noise)...this would happen only once, then she fires up. Again, only noticed this recently.

Is the backfire indicative of a cylinder accumulating fuel mixture but not igniting due to the presence of water, then when it finally ignites it explodes, clears the dirty water/fuel mixture, and subsequently fires up on the next turn of the key?

 

[guitman32]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

Any head bolt or exhaust cover bolt on a "salty motor" would make me nervous...especially the smaller exhaust cover screws. THey are easy to break...then what a pain and possible nightmare. If you do end up breaking a bolt/screw, do not use "easy outs"...take it to a machinist to have them removed properly without further damage.

MAybe some "pros" can chime in on their tricks to avoid breaking them in the first place.

Mas

Absolutely, I shouldn't be any more at ease with the exhaust cover bolts. Though I will say that if appearances count for anything I would say they've been either removed or replaced more recently than any other bolt on the ol gal; they are the freshest looking bolts in the entire engine.

Aside from the usual soaking in PB Blaster, I plan to hit them with an impact driver (hand held hammer type, not an air impact driver) on tighten first, then one rap on loosen...then re-soak in PB. Hopefully that will be enough.

Would anyone care to offer any other tips to help prevent snapping the bolts?

 

[emdsapmgr]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

It is not unusual for an engine to occasionally backfire during a cold start. Usually that is indicative of a lean condition. When you first start it, the engine needs enriching. Once the engine starts, you may need to occasionally bump (push in) the key switch to add extra fuel during the first minute of running. That should keep the engine from occasionally backfiring. Your specific engine also has a special cold starting feature called "Quickstart." A nice feature. When your engine is cold, the power pack will automatically advance the timing a few degrees. This timing advance aids in cold starting/initial running. Once the powerhead warms up to 92 degrees, this advance ends and the timing returns to normal.

 

[mkay]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

A lot of white smoke generally means a water leak and the smoke is mostly steam. The spark plug pretty much confirms this. Running this engine could lead to a catastrophic failure. If cold water leaks onto a hot piston top it may crack. It would probably be a good idea to pull the cylinder heads and investigate the affected cylinder. Compression of 85-90 psi is low even cold and could indicate cylinder scoring another possible effect of water intrusion. The recent very cold snap down into Florida has probably lead to some freeze cracks in engines that sit undrained. Some blocks have passages that can hold water. Most outboards drain naturally so it is rarely a problem if they are stored in the upright position. Good luck

 

[guitman32]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

A lot of white smoke generally means a water leak and the smoke is mostly steam. The spark plug pretty much confirms this. Running this engine could lead to a catastrophic failure. If cold water leaks onto a hot piston top it may crack. It would probably be a good idea to pull the cylinder heads and investigate the affected cylinder. Compression of 85-90 psi is low even cold and could indicate cylinder scoring another possible effect of water intrusion. The recent very cold snap down into Florida has probably lead to some freeze cracks in engines that sit undrained. Some blocks have passages that can hold water. Most outboards drain naturally so it is rarely a problem if they are stored in the upright position. Good luck

Thanks for the advice, my compression was actually an even 100psi across all cyl when I checked a few days ago after discovering this issue.

 

[guitman32]

Re: Take a look at my plugs and tell me what you think - 1989 Evinrude 175

It is not unusual for an engine to occasionally backfire during a cold start. Usually that is indicative of a lean condition. When you first start it, the engine needs enriching. Once the engine starts, you may need to occasionally bump (push in) the key switch to add extra fuel during the first minute of running. That should keep the engine from occasionally backfiring. Your specific engine also has a special cold starting feature called "Quickstart." A nice feature. When your engine is cold, the power pack will automatically advance the timing a few degrees. This timing advance aids in cold starting/initial running. Once the powerhead warms up to 92 degrees, this advance ends and the timing returns to normal.

Got it..I use the choke to start, but don't over-do it as I am cautious of flooding the motor. More choke from now on. Any I agree on the quick start being nice, the advance timing and high idle really keep her going...unless you've got issues like mine of course.