87 omc 350, no power, Help!

[subcrx]

Was out on sunday cruising to a fishing spot. Was on plane for about 30 minutes, and motor started dying, Came off of plane and motor died. I looked at the gauges and noticed temp was a little higher than normal but not really hot. I checked out the motor and It started back up, was kind of rough and noticed steam or some kind of smoke coming out of the valve cover breathers that go into the carb. So much of it was coming out that i had to pull the hoses off the carb because the steam or smoke was choking the carb and causing it to stall. I tried to get back on it and there is just no power, cant get over 3300 rpm. I don't know what to check, everything looks fine from what i can see. Any suggestions?

 

[rybad]

Re: 87 omc 350, no power, Help!

I'm not sure what climate you have there in Fullerton CA, but it sounds to me like a coolant leak. Head Gasket, or cracked block letting water into the cylinders - cooking it, and making steam.

Check your oil, make sure you dont have a milkshake going.

 

[subcrx]

Re: 87 omc 350, no power, Help!

i did check the oil, in fact I checked it a lot of times on the way in. No milkshake. Here in Fullerton its starting to heat up, water was around 60 degrees that day. I'm going to put it in the water tomorrow and check everything out.

 

[sarantis]

Re: 87 omc 350, no power, Help!

check also compression and plugs.if they are ok i would connect a tranparent flexible hose from the tank's outlet to the filter's input and after that from the pump's outlet to the carb's input and somebody to watch it .If it's completely ful of gas flowing through it i would think about the carb.Before that replace the fuel filter(water separator).

 

[sarantis]

Re: 87 omc 350, no power, Help!

When the engine dies it's normal to notice increased temperature.

 

[Bt Doctur]

Re: 87 omc 350, no power, Help!

Had a V6 doing the same thing, after the compression test we found a broken valve spring on a exaust valve. it was sucking some water back in. Try looking at the spark plugs, I`ll bet atleast 1 of them is pure white.

 

[subcrx]

Re: 87 omc 350, no power, Help!

I replaced the fuel and water separator yesterday so thats out of the way. I cut it apart and looked fine. I had the carb rebuilt over a month ago and Ive had two trips with no problems till this. I plan on checking everything. Gunna start with fuel, then check compression. I know spark is fine cuz i shocked the **** out of myself 8 times.

 

[Bt Doctur]

Re: 87 omc 350, no power, Help!

your first post is EXACTLY what was happening .water vapor was getting into the crankcase and we had to remove the vent line from the valve covers or the engine would stall. After changing the oil it too almost an hour to purge the water vapor out before we could hook the hoses back on the flame arrestor.

 

[subcrx]

Re: 87 omc 350, no power, Help!

interesting to know, maybe i should check compression before heading over to the launch ramp

 

[Bt Doctur]

Re: 87 omc 350, no power, Help!

And if I was to make a guess ,it will be a inner valve spring on a exaust valve. Very easy to detect if you pull the valve cover, can almost push the valve down with hand pressure.
Post the conclusion of your tests.

 

[subcrx]

Re: 87 omc 350, no power, Help!

I will you bet, Compression comes first tomorrow morning. it actually all makes sense now

 

[subcrx]

Re: 87 omc 350, no power, Help!

What are the chances of damage to the cylinder since I am running raw water and in salt, I did do a good ear muff flush before we went home that day.

 

[Bt Doctur]

Re: 87 omc 350, no power, Help!

Most likely no damage, if you hurry. Let it sit and thats when trouble begins.

 

[subcrx]

Re: 87 omc 350, no power, Help!

just got back, low compression number 7, only 40 psi if that. I pulled off the manifold on that side, water was level with that exhaust port and above the one behind it, water fell into the one behind it when doing compression test, I better get moving fast. All valve springs look ok, Im guessing blown head gasket.

 

[subcrx]

Re: 87 omc 350, no power, Help!

maybe just replace the heads while im at it. The valve stems and seats looked really rusted up

 

[Bt Doctur]

Re: 87 omc 350, no power, Help!

I`ll still go with a broken valve spring as my first choice,
2nd "Tuliped valve"
3rd burnt valve
Were all curious as to what it is.
Head gaskets will usually blow between adj. cylinders, not just 1 cylinder

 

[subcrx]

Re: 87 omc 350, no power, Help!

I tried pushing on it like you said when it was at a compression stroke, wouldn't go anywhere. Im gunna try and pull the head off asap. Ill post photos of what i find for you all. What exactly is a tuliped valve? I work on honda cars for a living and all Ive seen are burnt and bent valves.

 

[Bt Doctur]

Re: 87 omc 350, no power, Help!

You`ll know it when you see it,wont look like a normal valve face.
shaped like a "Tulip"

 

[subcrx]

Re: 87 omc 350, no power, Help!

got the head off of the side where there was no compression on no 7. After I got it off I felt no need to take off the other side. The valves looked fine. Once I looked at the piston I started crying. Its missing a large portion of it to the left and the compression ring is exposed. This cylinder looked white compared to the others. Lots of water damage. I have no idea how the water was getting in there. you could see a stream of rust below where the exhaust manifold bolts up to that port. Water was getting out there. here is a picture, hope it works

 

[subcrx]

Re: 87 omc 350, no power, Help!

need feedback here. replace the motor?