Honda BF5A 1999 wierd running issue

[artk]

Heya all,


I have a 4 stroke 5hp 1999 honda outboard my brother bought on ebay a few years ago. Ive been trying to revive it over the last few days and i hit a wierd running issue i cant figure out. Ive cleaned the carb, checked the valves and connected the prop/gears. I put a bucket of water and put the motor up on the stand and it starts right up first pull and pees water and purrs like a kitten.

heres the thing, once i take it off the stand and put it on the boat, it sounds like it is deprived of something and barely runs (sometimes doesnt even start). Over time i figured out that it is related to either the tilt of the boat or the depth, so if i have someone sit in front of the boat the motor will run somewhat because the boat is leveled. but if they move over to the back with me- the motor will cut off.

Im thinking it could be something with the float bowl, but this is my first time with a outboard so im not sure.

Thanks

 

[pwiseman]

Re: Honda BF5A 1999 wierd running issue

Heya all,


I have a 4 stroke 5hp 1999 honda outboard my brother bought on ebay a few years ago. Ive been trying to revive it over the last few days and i hit a wierd running issue i cant figure out. Ive cleaned the carb, checked the valves and connected the prop/gears. I put a bucket of water and put the motor up on the stand and it starts right up first pull and pees water and purrs like a kitten.

heres the thing, once i take it off the stand and put it on the boat, it sounds like it is deprived of something and barely runs (sometimes doesnt even start). Over time i figured out that it is related to either the tilt of the boat or the depth, so if i have someone sit in front of the boat the motor will run somewhat because the boat is leveled. but if they move over to the back with me- the motor will cut off.

Im thinking it could be something with the float bowl, but this is my first time with a outboard so im not sure.

Thanks

Since you say this is your first outboard - Is the transom on the boat the same as your shaft length on the motor? The cavitation plate above the prop should be very close to the bottom of your boat. If it is sitting down 4 or 5" you have a long (20") shaft motor on a 15" transom.

 

[longshanks]

Re: Honda BF5A 1999 wierd running issue

hey ARt

I'm thinking that you have that motor mounted too low. I have a BF5 also, and it doesn't run well at all, over extended periods, if the exhaust port is bubbling away under water. The exhaust port has to sit above the water level, while operating. I am pretty sure this was a contributing factor to the only problem I've ever had with my Honda 5 -- I lost some oil out of it. I think hte back pressure created by exhaust forced some oil out of the carbs.

Try mounting it higher, I think it may solve your problem.

Shane

 

[lexi]

Re: Honda BF5A 1999 wierd running issue

What about engines with through hub exhaust? Do they suffer backpressure? Outboards are not usually that sensitive to running angles........hence their ability to run on shallow trim etc. You could have a leaky exhaust which is blowing more when slightly pressured and choking the engine. Clean float jet and reset also.

Alex

 

[artk]

Re: Honda BF5A 1999 wierd running issue

My boat is a a standard aluminum 12 or 14 foot, its 15.5 inch deep at the back so it should fit a short shaft fine, which it does.

The exhaust port sputters out some water along with the exhast, I thought that was normal but could that be a symptom of a leaky exhaust? or how would i check the condition of the exhaust?

Ill take a look at the float system again today.

Arthur

 

[Jellyfish12]

Re: Honda BF5A 1999 wierd running issue

Is there any way you could duplicate the problem in the bucket of water, this might make it easier to see where the problem. For example raise the water level until it runs like crap, or tilt the motor and so on.

 

[lexi]

Re: Honda BF5A 1999 wierd running issue

Your exhaust emits burnt gas while water is added for cooling.......it is normal for a spray of water to come out with the fumes. Take your hood off when running to see if motor improves. If it does you have an exhaust leak which is choking the carb of air in the enclosure of the hood space. Try tilting the motor up to shallow drive ...see if it runs on boat in that position. Is tickover set correct.? It is quite high on that motor. Guess about 1050 revs.

Alex

 

[longshanks]

Re: Honda BF5A 1999 wierd running issue

Art, I just looked in my owner's manual. It says

'when the outboard is installed extremely low, the idle port may be immersed, and the engine may become hard to start or may run poorly. Check that the idle port is high enough from the water level when the engine is stopped with the engine fully loaded'

Note as well that mine sputters water out the exhaust, as Lexi describes.

My BF5 has been a fairly good motor for me. Quiet, and reliable. I wouldn't describe it as a smooth runner, but this is probably because it is a single cylinder. This summer, I have had some problems with oil leaking from the motor. I have no idea how this happened, but maybe during transport.

 

[lexi]

Re: Honda BF5A 1999 wierd running issue

During journeys up and down hills the motor sometimes sits with the powerhead below the prop. If valves are open this could cause the oil to come out. If you take up the compression with pull start it should close the valves before you store outboard in car. Works for me.

Alex

 

[longshanks]

Re: Honda BF5A 1999 wierd running issue

Lexi, my motor seems to be sporadically losing small bits of oil lately. Maybe it is unrealistic, but I'd like to think that my four stroke outboard isn't leaving any oil in any of the small, pristine lakes that I boat on.

I have tried to find leaking oil, while running it in a tank at home, and it doesn't seem to be obviously leaking. As I said, I expect this leakage is resulting from transporting the motor. It gets carried to and fro, and lies on it's (proper) side, in the back of my pickup.

Can you explain how I would go about closing the valves with the pull start, before I take it off the boat?

thanks

 

[dbq6]

Re: Honda BF5A 1999 wierd running issue

You may also want to run the gas completely out of the carb before shutoff. The gas in the bowl leaks out during transport sometimes, dries some on the inside of your cover, and looks oily. Shut the gas off or disconnect the fuel line and run the engine until it runs out of gas.

 

[artk]

Re: Honda BF5A 1999 wierd running issue

Well, i took apart the carb again, checked the float and gave the jet/nozzle a good cleaning. I also replaced the spark plug and gas tank/line and filled it up with higher octane gas. It seems to run better and less sensitive to tilt, but i dont think it is getting its full 5hp out, runs very slow on full throttle and stalls after a few minutes if you lay off the gas.

I also smelled gas in the oil- but that may be related to when i first got ahold of the motor and the main nozzle was missing. May have been a serious overflow of gas that got past due to the rich condition.

Anything else to check? This was an ebay purchase so it could be damn near anything.

I would take it to a shop to troubleshoot the issue if there is a reputable mechanic somewhere.

 

[artk]

Re: Honda BF5A 1999 wierd running issue

Also forgot to mention the exhaust port is about 1-4 inches above the water line depending on how much weight in the back of the boat- Which should be acceptable i think.

 

[lexi]

Re: Honda BF5A 1999 wierd running issue

That is about the same as my five sits on boat. Have you really cleaned carb with compressed air and carb cleaner? Also check valve clearance. The five hp gets to full power very quickly and after half throttle it does not produce any more. It is rather a slogger. To close the valves merely take up the tension on pull start till you feel that pressure. Make sure there is not too much oil in sump. Better slightly underfilled actually.

Those 5 hondas are dinosaurs...but I like em. It`s unusual for Honda to continue with the same engine unchanged for 30 yrs

Alex

 

[Dream]

Re: Honda BF5A 1999 wierd running issue

Having similar problem with my 1996 Honda5: runs fine with hood off but chokes with it on. Could it be pressing on throttle rod? Or how do I find if exhaust leaking inside hood? Any ideas.......(exhaust outlet is correctly below waterline).

 

[lexi]

Re: Honda BF5A 1999 wierd running issue

your problem is a leaky exhaust.............maybe corroded. when lid is on fumes are choking motor.

Alex

 

[Dream]

Re: Honda BF5A 1999 wierd running issue

Thanks Alex. Will check it out next weekend.

 

[Dream]

Re: Honda BF5A 1999 wierd running issue

Many thanks for tip Alex: yes, now traced to a corrosion hole in exhaust manifold which hopefully some liquid metal will cure. Otherwise looks like a major job to replace....