Ran out of water... did i get away with it..?

[pyro225]

Hi all,

took the boat along the rivers on Saturday as it was a great day... the water however was the lowest I've seen it - only 2-3ft deep in some parts! Anyway I (as always) was going along checking the tell tale of my merc 80 (4cyl 1986 )every so often as you do (probably between 3-5mins). Anyway was cruising along maybe 1/4-1/3 throttle and I start smelling a nasty smell (oily / metallic) and then I turn around and see white smoke coming from the outboard - not 2 stroke oil! as I turn around it makes a metallic chattering sound so I immediately try to turn it of.

As I turn the key it still runs! I pull the emergency cord its still running! eventually about 30 seconds later it dies so guessing it was hot spots on the plugs...

Anyway as expected there were reeds blocking the water intakes both sides so I quickly cleared them and tried to start her up to get her cooling...

I must have tried 40-50 times to start her but she didn't want to know and my heart was sinking fast... then as if by magic she fired up for about 10 seconds and died... tried again at 3/4 throttle in neutral and she fired up and was pumping water - which was great... but was still making the metallic chattering sound... not great - so I left her idling for about 5 minutes at 3/4 throttle and then suddenly the chattering went away...

I then drove her back about 8 miles and she ran better than she has done for a long time!

So what's the chance I got lucky and what's the chance of some serious damage?

Also is there anything you can install to indicate no pumping?

Thanks

Dan

 

[racerone]

Do a compression test and take action on those results.---Post your numbers.

 

[gm280]

Oh the metallic sound is never a good thing. And I don't believe it healed itself either. I'll be watching your compression results... :facepalm:

 

[pyro225]

looks like the compression testers is coming out... only thing is how do you get to the bottom cylinder and I cant even get a socket in there! if they had low compression wouldn't it run rough/not at all?

 

[pyro225]

Scrap my last question - bought a new tester with a smaller end ok... ready:
Top Cylinder:
1: 135
2: 141
3: 140
4: 142
Bottom

What do you think from that?

Side question - I am sure some of you have seen my other post about a 50hp o/b merc that struggles to start - as I had the tester out I went to try and use it but as it a pull start I gave it say 10 pulls but even on the same cylinder the results (di d10 pull 3 times) were completely different going from 90 to 130 - how can I get an accurate result? i'm guessing the higher the number the faster i'm throwing it over?

Thanks

 

[gm280]

Scrap my last question - bought a new tester with a smaller end ok... ready:
Top Cylinder:
1: 135
2: 141
3: 140
4: 142
Bottom

What do you think from that?

Side question - I am sure some of you have seen my other post about a 50hp o/b merc that struggles to start - as I had the tester out I went to try and use it but as it a pull start I gave it say 10 pulls but even on the same cylinder the results (di d10 pull 3 times) were completely different going from 90 to 130 - how can I get an accurate result? i'm guessing the higher the number the faster i'm throwing it over?

Thanks

Okay pyro225, if those are your true compression readings, and I'm not doubting you one bit but just making sure the gauge is correct, then you don't have a ring/piston or cylinder issue to worry about. But you still have rod bearings and crankshaft main bearing that could be compromised as well. But only running it will tell over time, and I honestly hope so... :thumb:

 

[Sea Rider]

You could have already a faulty head gasket and not knowing anything about that, or on its way to become severely shot if continuing using that engine after overheated. When an engine overheat occurs due to water pump intake failure as when obstructed, a head re torque to factory specs is mandatory. One issue is idling an engine or running at low speeds, other story is going 3/4 throttle to full wot under overheated conditions

Happy Boating

 

[pyro225]

Sea rider- are you saying if the head gasket is gone it might have a bad idle? So are you suggesting I should re torque the head bolts before using again

 

[racerone]

???????----There is no cylinder head on that motor !!------Not sure why folks keep posting that fix on these Mercury motors.

 

[pyro225]

Racer one didn't think there was as there are no valves but was checking - so I. Your opinion do you think I'm ok? I meant to do a compression test before as it has a low down misfire when in gear. If the compression looks good where would you start with that? Also any ideas how to test a manual start?

 

[racerone]

I would inspect the water pump impeller.---those motors need a new one about every 3 years or so.---Remove the upper bypass cover and have a look at the pistons and rings.