1999 Honda 50hp Four Stroke with Power Tilt & Trim

[jimbobule]

I have a chance of buying a nice boat with this carb version engine. Problem is that it is not working correctly.

It fires up, then idles slightly too high. Can only make 4 knotts over the water. Push any higher and it just cuts out but restarts again.

I'm also told that when it was going OK, it was making only 60% of speed WOT (i.e 14-15 knots versus 20) and over revving.

Any ideas? Does this sound like a major or minor issue?

Your help is appreciated.

 

[hondadude]

Maybe, maybe not.

Last statement first...re over revving. Not knowing what size or type boat...it sounds like it is a heavy boat or a pontoon boat. If the motor is overrevving, it generally means the pitch of the prop is too low or the engine is mounted too high and the prop does not have enough water to dig into or it is trimmed too high. None of which should be a major problem, unless the motor is too high and you physically can not lower it.

As for the poor run-ability, it is anyone's guess. Not knowing if you have much mechanical skill, tools or desire.....the compression and spark should be checked. If the compression is bad (should be around 200 psi at wide open throttle), it is time to take a giant step back and reconsider.... If you do not have the ability or tools to check it out, I recommend that you take it to a Honda dealer, who has worked on 50's for a while. They should be able to tell you if the engine is sound and maybe just needs the carburetors cleaned. Once the motor is running properly, it will take some experimenting to find the right size prop.

It is also possible that the fuel has water in it and the engine just needs a good flush.

The idle is probably set high to keep the motor running, since it is probably only running on a two of the three cylinders. Again, that could be a bad cylinder or just dirty carburetor.

If the boat has been sitting for a while, it is a good chance that it was not put away properly and it is just the carburetors.

Also, check the oil and the oil level. Dirty oil indicates neglect. If the oil is too high, it could be either they just put too much oil in or the unburnt fuel is leaking past the rings....another indication of carb problems or could be carbon build up. Spark plugs should be pretty clean, if it is running right.

I feel that I am just sort of rambling at this point. Mostly, just to let you know, there are many reasons for the poor performance. That is why I recommend taking it to a "good" dealer....not a mechanic who says they work on anything. (I hope I did not offend anyone) There are specific things to look for on this engine.

The engine itself is a very strong engine and can take a lot of abuse. So, all the basics check out, I would not hesitate to buy it, but be ready to put some work into it (if you are doing the work yourself) or put some additional money into it (depending on how much has to be done).

If you purchase it, unless the seller can document that the water pump was just changed, I would change the water pump to be sure the cooling system is working correctly from the start.

If you are going to do the check out yourself, let us know and I and others will get more specific on the how to's.

Good luck..

Mike

 

[jgmo]

There's an old saying in the auto industry about making a quick assessment of an engine. It goes something like:
If it starts and idles, then it is PROBABLY fairly sound.

Having said that, there is another old saying about pretty much everything...Buyer beware!

Mike has given you some good things to consider and his opinion reigns supreme around these parts.

After verifying fuel quality, one thing you might want to try is to get her running and then, using some insulated pliers or DRY leather gloves, pull each plug wire, one at a time, and see if each cylinder makes a difference in the way it "idles". If you find one that doesn't, then you know for sure that cylinder is essentially "dead" and that is where the investigation should start. Buying an engine with a dead hole is really like going to Las Vegas and hitting the craps table. You could come out smiling or crying.

If you find a dead hole then you SHOULD NOT buy unless you find out why the cylinder is not firing. It could be a plug, a wire, the carb or....something worse. If it is valves or a broken ring, you will be in for power head work and that can be expensive. If the owner won't let you do a compression test or a leak down test then I would walk away.

If they are all contributing then it is likely the running issues will probably be a "manageable" endeavor. Rebuilding all the carbs isn't all that simple but it's not overly difficult either and is relatively inexpensive. If that is what is necessary.

Good luck and I hope you get a good deal.

 

[aliboy]

We have put quite a few 1000's of hours on BF50s now and I like them. Seem to be pretty tough, so you may only have reasonably simple issues to deal with. I would start with a compression test first up. If they are not OK, probably walk away unless you get a rebuild built in to the price. If all the compressions are OK, then most of the other potential causes are not crazy expensive to fix. Pretty sure that I even have spare CDI unit for one of those lying around somewhere, not that that is likely your problem. If the comps are good, I would service the carbs next. Other than that there are a few electrical items that might cause the problem and none of them are that hard to fix.

 

[chawk_man]

Agree with all of the above, but I always try to eliminate the simple things first. If you get a chance to run the boat again, when it tries to stall, open up the fuel tank filler cap just to make sure the tank is breathing right. Also, check the pump up bulb to make sure it is not partially collapsed, which would indicate a partially blocked pick up tube in the tank. If that doesn't do it, then try squeezing the pump up bulb rapidly to see if that straightens it out.