2004 honda 50 smoke, power and compression

[gcarmich]

My 2004 Honda 50 4-stroke doesn't seem to have the power I would expect. This season I noticed light grey smoke often coming from the prop exhaust. I checked the valves and they are fine. Compression test varied between 160 and 170 PSI (manual suggest 212+-14 PSI). Should I be concerned that something is wrong with the engine?

 

[hondon]

Re: 2004 honda 50 smoke, power and compression

How did you achieve those compression numbers?These things have to be at wide open when that test is accomplished.Keep in mind that compression guages can vary widely.Those numbers are least even and thats what you want to see.Gray smoke?Look at the dipstick and filler cap.Run that dipstick across your finger and it should have the appearance of oil.That filler cap should have little or no white foamy buildup.Take a fuel sample direct from your fuel tank and let us know how much water is in there.

 

[gcarmich]

Re: 2004 honda 50 smoke, power and compression

Thank you for your response. We measured the compression using the method specified in the Honda service manual. I held the throttle at WOT and pressed the compression guage against the plug hole while my friend turned the engine over with the kill switch clip removed.
I was on the boat today and took a closer look at the smoke - it is coming from the exhaust port below the engine cover (well above the water line)- not the prop exhaust. The oil looks good and there is no white foam on the filer cap. The oil level is at the top of the dipstick mark - could it have too much oil ?

 

[hondon]

Re: 2004 honda 50 smoke, power and compression

When is the last time that oil was changed?Keep in mind that these engines make oil and even though the level is correct,it does'nt mean that oil is not washed out.This is especially true in cold water and we've kinda all been there this year.That exhaust port under the powerhead is an idle relief and will deliver some steam from time to time and on a cold day ,practically,always.This is a carburated engine,so weather can effect performance a great deal.I'dd still like to know about that fuel sample.

 

[gcarmich]

Re: 2004 honda 50 smoke, power and compression

I changed the oil and filter about 6 months ago. I used a synthetic oil. The oil is still golden in color and feels and smells like new oil. The engine is only run a couple of times a month. I'll get a sample of the fuel and find somewhere to get it tested.

 

[marquette]

Re: 2004 honda 50 smoke, power and compression

does the 50hp use synthetic oil? honda told me not to use it on my 1998 30HP. it would be interesting to know if they reccomend it on some motors and not others. and the better question would be why?

 

[gcarmich]

Re: 2004 honda 50 smoke, power and compression

Honda's shop manual for the BF35A, BF45A engines specifies SAE 10W-30 API Service Classification SG,SF/CC, CD.

 

[Lundman]

Re: 2004 honda 50 smoke, power and compression

When is the last time that oil was changed?Keep in mind that these engines make oil and even though the level is correct,it does'nt mean that oil is not washed out.This is especially true in cold water and we've kinda all been there this year.That exhaust port under the powerhead is an idle relief and will deliver some steam from time to time and on a cold day ,practically,always.This is a carburated engine,so weather can effect performance a great deal.I'dd still like to know about that fuel sample.

What do you mean when you say that these engines "make oil"? I am not sure what exactly that is suppose to mean. I've heard of using/burning oil,
but "making oil"?

 

[pvanv]

Re: 2004 honda 50 smoke, power and compression

Check the FAQs on that. 4-strokes are subject to oil dilution. They do make oil, and synthetic makes it a bunch worse.

 

[OBMD]

Re: 2004 honda 50 smoke, power and compression

4-stroke motors that do not come up to proper operating temperature will allow unburnt fuel to blow past the rings. I would suggest that you install a hotter thermostat. Honda has a 162F thermostat. Standard thermo is 126F. The part number is 19300-ZV5-043.