Runs fine on Land not on Water

[Matty8251]

OK I have a 1988 Bayliner with a 181ci 3.0L OMC and 3.0L OMC Stern Drive. We where out skiing and it was fine I shut the motor off witched skiers and restarted it and had no power. I can't get the boat over 2500RPM's and about 10MPH at WOT. the boat just doesnt sound right in the water, but sound great out of the water, with no problem hiting max RPM in gear or out. No leaks or fluid where it shound not have been. I have no idea.

 

[rs2k]

Re: Runs fine on Land not on Water

It sounds like you lost some power and now the engine isn't powerful enough to get out of the hole. I would check your fuel filter, fuel pump, spark plugs, plug wires, ignition timing, etc.

 

[Matty8251]

Re: Runs fine on Land not on Water

power lose in a understatment. I have check all the fuel and igntion related stuff. This one really has me thinking.

 

[rs2k]

Re: Runs fine on Land not on Water

Maybe you have a spun prop hub. You may also have a burned or butterflied exhaust valve. A compression check would tell you the status of your engine.

 

[searay3]

Re: Runs fine on Land not on Water

Never run the motor at high rpm on the muffs. It tells you nothing and you risk frying the impellor (the hose may not keep up enough water volume) Look for water in the fuel. Dump the fuel filter in a glass jar and look for water separation. You may need to add a fuel water separator. One question...when was the last full tuneup, plugs,cap, rotor and fuel filters (at least 2)

 

[rs2k]

Re: Runs fine on Land not on Water

Don't forget to check the filter inside the carb.

 

[BadBay400]

Re: Runs fine on Land not on Water

I had the same problem with a friends boat . His ended up being a voltage problem . The alternator wasn't charging enough . after about a half hour on the water (radio on , depth finder , all that kinda junk) the voltage would drop . There wasn't enough power for the ignition to properly ignite the fuel . Then the boat wouldn't rev . Just somthing to check .

 

[Matty8251]

Re: Runs fine on Land not on Water

A full tune up was done 2 months ago. The only thing that I did not change in the coil. All filters, wires, plugs, points, cap, and rotor are changed every year. I use Stabil Marine at each fill up of the fuel tanks.

I am going to get a new coil and then go from there.

On the altermator thing I though of that but I am putting out about 14 volt of charge to the battery.

I see someone else is having the same problem, they just posted it today.

 

[Matty8251]

Re: Runs fine on Land not on Water

With a inline pressure tester I have between 6-7psi of fuel pressure coming into the carb. Also I check by putting a vac pump on the inlet side of the fuel canister and held 10"hg. From what I read that is where it should be. The only thing between the point I tested it and the carb bowl is the small fuel filter and spring. I have went and checked all the measurments on the float hight and drop and it was all correct.

I just went and pulled a freinds carb off and ran the boat with the same result. When pulled the spark plug when I got it out of the water and they are wet. To me, this tells me that I am getting fuel and that the spark is not doing its job.

If that is incorrect then please someone tell me, I am losing ski days one after another.

 

[searay3]

Re: Runs fine on Land not on Water

Have a look at the advance weights in the distributor. If you have or have access to a timing light w/advance, it could be it's not advancing as it should.

 

[Don S]

Re: Runs fine on Land not on Water

With a inline pressure tester I have between 6-7psi of fuel pressure coming into the carb.

That isn't the only test of the fuel system. That tells you the fuel pump is working. What happens at full load? Is the pump getting gas? or is something blocked to keep fuel from getting to the pump.
Go to the link below and read item #3.

http://forums.iboats.com/showthread.php?t=288430

 

[Matty8251]

Re: Runs fine on Land not on Water

This is great info thanks you. I will try the tests that are on that page. The one thing I still not get is why where the plugs where wet when I pulled them??? That one still gets me.......

 

[Don S]

Re: Runs fine on Land not on Water

The one thing I still not get is why where the plugs where wet when I pulled them???

Wet with what, water, gas, and how sure are you if it was gas or water.
You may very well have gotten water in the cylinders, especially if you shut it off and it either diesel, or you shut it off and the wakes from the boat hit you.

Personally, I have customers come in all the time and say their engine "Sounds Fine" only to find that it sounds like 'ell. when I start it and listen to it on muffs. I've heard cylinders with no compression, plug wires crossed, you name it. But always told that the engine runs "Fine"
Kind of like hearing the wife say "FINE" while she glares at me. It's NOT fine.

 

[Matty8251]

Re: Runs fine on Land not on Water

Wet with fuel, 100% sure. I know 91 octane anywere. I just pulled a fuel sample and am letting is sit for a while but it did not have any oil or water in it that I can see right now. Even with swirling it I did not see any water. ( it will bubble)

 

[Matty8251]

Re: Runs fine on Land not on Water

I think I found the problem, I got a compression tester today and found the #1 to be at 126psi, #2 26psi, #3 25psi and #4 at 117psi. So I will find out with some air if it is the vavles for the pistons later today.

 

[rs2k]

Re: Runs fine on Land not on Water

It sounds like a blown head gasket, cracked(or warped) head or cracked block in that order of likeliness.

 

[Don S]

Re: Runs fine on Land not on Water

I got a compression tester today and found the #1 to be at 126psi, #2 26psi, #3 25psi and #4 at 117psi.

EXACTLY what I was referring too. It was NOT running fine on land. It was just barely running. When you put it in the water it flat said no.

Half the cylinder are dead.

Do a leakdown test to determine what is wrong, or pull the head and have a look. Personally, I would do a leakdown test since the cylinders are side by side.

 

[Bifflefan]

Re: Runs fine on Land not on Water

From the sounds of it, id try looking for a jumped timing chain/belt. Especially if you dropped RPM's fast and then shut if right off. If its off one tooth it will run but not good.

 

[rs2k]

Re: Runs fine on Land not on Water

EXACTLY what I was referring too. It was NOT running fine on land. It was just barely running. When you put it in the water it flat said no.

I had a Chevy 305 that had two VERY blown head gaskets and two VERY cracked heads. You could see the cracks from about 5 feet away once the heads were pulled. That engine just seemed to run great when not in the water as well. You really need a load to see what an engine will do.

 

[Don S]

Re: Runs fine on Land not on Water

I had a Chevy 305 that had two VERY blown head gaskets and two VERY cracked heads. You could see the cracks from about 5 feet away once the heads were pulled. That engine just seemed to run great when not in the water as well. You really need a load to see what an engine will do.

I'm sorry, but cracks don't always lower compression, and when you have that (25psi) low compression on 2 out of 4 cylinders, it doesn't run "FINE".
It sounds like crap, and you can't set the timing or anything by the book.
All you can do is turn the distributor till it smooths out and adjust the carb to the 2 good cylinders. Of course when you put it in the water, it won't run.

It most likely has a bad head gasket. VERY common on the 3.0l engines when run with the wrong timing. This also caused errosion of the head and block to the point a new engine was needed.