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1997 Honda 25hp 4stroke problem

ryans01z28

Contributing Member
I bought a boat from a guy with a 4 stroke on it and it was doggy from tiring so long so I pulled the carbs off and cleaned them up with some carb cleaner. The next morning I put the muffs on it and it still seamed doggy so I unhooked the gas line and ran the motor off of some b12 carb cleaner then took it out on the water. Now the boat ran worse than before and finally just died out on me after a about 5-10 minutes of trying to run the dog crap out of it. I tilted the motor back so I could use the trolling motor to get to shore and when I did water came pouring out from under the cover WTF! I got it home and the oil was full of water, the carbs were full of water and I had water in the cylinders. What the hell happened here?
 
First thing that comes to mind is water in the fuel.

Pull the connector off the end of the fuel line going to the engine and squeeze some of the fuel into a glass jar to see if there is any water in it.

Two other possiblities....

1 If you pulled the carbs off as a set at the intake manifold and did not replace the intake manifold gasket, you will probably get water sucked in there. That will not be the source of water in your carburators themselves though.

2. You could have internal cracks in your engine.

Water in your fuel can put water in all the places that you are finding it. That is the most likely problem.

Mike
 
I don't know how water would of got sucked in from the gasket when the cover was on and the boat wasn't going more than 7mph tops. I put fuel in the tank but mayb there was water in the tank before I topped it off when I bought it. And I highly doubt there's internal cracks in the engine cuz it looks brand new. Could I get cracks inside over the winter if it's not winterized???? It just seems funny cuz I ran the boat before I tore the carbs down but It was sluggish assuming the small ports were plugged from old gas so I don't think there's cracks internally. Almost sounds like water in the fuel I guess
 
Just listed some possibilities. I agree, most likely you have water in your fuel.

The way water can get in around a bad intake manifold gasket is...there are water passages right next to the intake passages. If the passages are not sealed completely, the water goes from the water passage directly into the combustion chamber.

Mike
 
I just checked the gas and that looks good, no water bubbles in it. So now does it sound like the gasket? I just pulled the carbs off and cleaned them and put them back on with out using a new gasket
 
You said your carbs were full of water....do you mean the carburator bowls or the throats of the carburators? I do not know how water would get to the carbs from a bad intake manifold gasket, unless the water pressure was so great as to send it in a reverse direction through the intake manifold and back into the carbs.

Run the motor on a hose and see if you see any water leaks on the engine....like the telltail indicator hose not being connected to the outside nipple.

When you run it on a hose, be sure to tape up the extra (third) water intake just above the prop on the antiventilation plate (horizontal plate just above the prop) so it does not suck air and burn out the impeller.

#35 is the gasket that I am referring to. See the two large holes between the three intake holes in the gasket...they are for the water passage to cool the intake. http://www.boats.net/parts/search/Honda/Outboard Engine/1998/BF25AW SHA /CARBURETOR/parts.html

If you are replacing it, be sure to clean the surfaces really good before you put the new one on. If it is not clean, it is just as bad as reusing the old gasket. (All the ones that I have done do not come off clean and take a lot of careful effort to get it off and clean).

Be sure to change your oil and filter to get the water out of there also.

Mike

Mike
 
The bowls were full of water yes. I had the muffs hook up to it and it was runnning off our well so maybe there was to much pressure and filled them up
 
That would be very unusual. I would recheck your fuel.

A simple way to see if there is water in your fuel....take out the fuel filter and dump it into a glass jar. If there is water there, then there is water in your fuel tank.

Mike
 
I had already put some in a clear bottle and didn't see any I did notice it was pretty orange however so maybe I should just dump it all and try new stuff
 
I now have another problem. I took the carbs apart (just the bowls) and cleaned them and put everything back together and now it won't even fire. After I drained all the oil out I was cranking it over withou the plugs in just to try to get some of the contaminated oil out from the water. Is there something I need to do to it like some kind of safety switch. The eye on he motor is green when I crank it over, I have really good spark, and there is fuel in the carbs so I don't know why it wouldn't start. Is it even remotely posible the timing jumped when I was trying to run the dog crap out of it and that's how the water got in everything????
 
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To check timing, you need to verify alignment of mark under flywheel and at the camshaft. They both have to align. To see the one on the crankshaft, you must remove the flywheel - at least you do on my 2001 model.

As for compression, if the timing of the camshaft is off, the valves could be open when piston is on compression stroke - thus resulting in no compression. Of course with the interference type engine that the Honda is - you'd also end up with piston meeting valve. I suppose there's a 'timing' that would close the valves just before the piston met the valve - but still allowed all compression to escape.
 
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To check timing, you need to verify alignment of mark under flywheel and at the camshaft. They both have to align. To see the one on the crankshaft, you must remove the flywheel - at least you do on my 2001 model.

As for compression, if the timing of the camshaft is off, the valves could be open when piston is on compression stroke - thus resulting in no compression. Of course with the interference type engine that the Honda is - you'd also end up with piston meeting valve. I suppose there's a 'timing' that would close the valves just before the piston met the valve - but still allowed all compression to escape.
You can see the timing mark on the flywheel in the pic. A guy said that has to lign up with the boss by the timing belt tensioner which it does. The pics show just how it sits right now so it looks as if the timing is right on. I just don't know why it doesn't have compression
 
From the angle of the picture, it does look like your timing might be off a little. The mark on the side of the flywheel does not seem fully align with the boss. It is impossible to see the part of the boss that comes out in a line to match up with the line on the flywheel.

If it does line up, it could still be out of time if the flywheel key sheared. You might be able to look under the flywheel for the timing mark that freeportd mentioned. If you can not see it, then you have to pull the flywheel to tell for sure.

Before you go through all that trouble, you might want to check your compression gauge on something you know works (like your car) to be sure that the compression gauge has not malfunctioned.

Mike
 
From the angle of the picture, it does look like your timing might be off a little. The mark on the side of the flywheel does not seem fully align with the boss. It is impossible to see the part of the boss that comes out in a line to match up with the line on the flywheel.

If it does line up, it could still be out of time if the flywheel key sheared. You might be able to look under the flywheel for the timing mark that freeportd mentioned. If you can not see it, then you have to pull the flywheel to tell for sure.

Before you go through all that trouble, you might want to check your compression gauge on something you know works (like your car) to be sure that the compression gauge has not malfunctioned.

Mike
If the timing is off a cog it should still have some compression shouldn't it? When I put my finger over the spark plug hole I can feel some compression. I'll see if my gauge is working right but it should be since its only been used a handfull of times
 
Do I time this enging just like the bf35a-bf50a? I ask this because I have a book now and when I go through the timing in the book it talks about the bf25a but the pics show them timing a bf35a-bf50a and where they line up the timing mark on the crank is opposite of where my mark on the crank is at the boss
 
Timing is similar. I think the marks are in slightly different places. The flywheel rotates clockwise on the 25 but the flywheel rotates counterclockwise on the 35-50...so be careful when they tell you to rotate the flywheel.

Mike
 
So last night I checked my compression gauge to see it it was working and it worked fine. I checked to make sure the timing marks got lined up and then I checked the compression again and I have no compression in any of the cylinders. What could of happened to this motor that has very few hrs on?
 
I'm still trying to figure this whole thing out as to why or how water got into the bowls and cylinder. If the timing jumped 1cog would it of hit 1 valve on all 3 cylinders and sucked water in? That's the only way I can figure out why I have no compression
 
I do not know. Maybe it did when you ran it really hard.

I have had a 25 in that jumped timing one notch and it just idled badly.

Hopefully, someone else has some theories. Jimmy usually does.

Mike
 
It doesn't make a lot of since to me how the bowls could have water in them and then the amount of water that was in the cylinders and the crank case was full Of water. The timing almost looked like it was off 1 cog but I'm not for sure
 
Hmmm, this is tough. You say you feel compression with your finger but see nothing on your gauge? I hate to say it to you but it is quite possible the water that got in the cylinders bent the rods.

These things only REALLY start to compress when the piston is just a few thousands of an inch from TDC even though, in our minds eye, it's all the way up the stroke. A very slight dimensional difference in the cylinder can make all the difference in the world.

That would also account for the slight misalignment you see in the photo of your CRANKSHAFT timing marks while the cam is perfectly aligned. Not really "one cog off" but not right.

You say you can feel compression with your finger but don't see it on the compression gauge. I'll bet that if you used a finer calibrated gauge, like one that reads 15 or even 30 psi, you would get a reading and each cylinder would be slightly different.

This is all assuming that you are performing the compression test now with the throttle propped all the way open, all spark plugs removed and the valves are all properly adjusted.
 
What is the compression supposed to be on these little engines? About 150psi?
I wonder if it would pay to order up a leak down tester? It looks as if we have an upcoming tear down
 
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Yes, test! The leak down tester is a good buy. They sell an adequate one for a reasonable price at Harbor Freight. I don't think a leak down will reveal any info on bent rods but I would still use mine prior to "going in". It might tell a whole different story. If you find leakage, then you can celebrate that you have not bent the rods.

Also, after thinking about my own comments, I realize that having bent the rods would not explain any shift in the position of the flywheel and, ultimately, timing mark. However, the force necessary to bend rods could possibly distort the crankshaft keyway or actually put a twist in the end of the crank as she came to a screeching halt. Hopefully, the key might have just sheared. Taking off the flywheel and checking that is far from a tear down and something you might consider.
 
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