gas consumption

[supragriff]

I am the second owner of a 1991 Sunsport. I have had it about 5 years now and it has less than 300 hrs. For some reason this year it seems I am using twice the gas I have in previous years. The boat seems to be running fine. The only thing I have noticed that I haven't before is a little white smoke coming from the exhaust. Any suggestions?

[87SunSportMikeyD]

((edit out talking from out my a$$ here) I think mine has been acting weird lately I get blue smoke when surfing and most other people say they do not. No more though with Fresh Air Exhaust heheh! But still want to fix the issue...

[Hematoma]

Running rich check your carb adjustments. I think mine has been acting weird lately I get blue smoke when surfing and most other people say they do not. No more though with Fresh Air Exhaust heheh! But still want to fix the issue...Mikey In most case blue smoke means your getting oil blow by. Your getting oil past your oil ring and its mixing with fuel in the cylinder.

[Hematoma]

I am the second owner of a 1991 Sunsport. I have had it about 5 years now and it has less than 300 hrs. For some reason this year it seems I am using twice the gas I have in previous years. The boat seems to be running fine. The only thing I have noticed that I haven't before is a little white smoke coming from the exhaust. Any suggestions?That white smoke is prolly steam. it can be mistaken for smoke.

[michael hunter]

If it has a holley carb check the power valve it might be blown that will cause excessive
fuel consumption.

[supragriff]

thanks! I'll check it.

[87SunSportMikeyD]

Thanks Hema! Is that oil ring something that is easy to check?

As for the power valve both SkiDIM.com and Holley's website have great instructions for VERY simple way to check power valve.

[Hematoma]

Thanks Hema! Is that oil ring something that is easy to check?

As for the power valve both SkiDIM.com and Holley's website have great instructions for VERY simple way to check power valve.Yes and no. You can try a leakdown test. Get you a compression test gauge from the autoparts store, remove your spark plugs and the plug wire running from the coil to the dist. Then screw the guage in each cylinder and spin the motor over to see what the compression is on each cylinder. If the rings are in decent shape they will hold pressure if not they will leak down not instantly but over x amount of time. Also if you vary a certain amount compression from one cylinder to the next it is pretty much time for a rebuild.

Example if the compression on the #1 was 135psi and #2 was 85psi and the rest of them are 125ish to 135ish that would tell you #2 is suspect maybe a bad cylinder, bad rings or that cylinder needs valve work. Lots of varables. Most important you want the compression to be pretty even or close across the board.

[Salty87]

I am the second owner of a 1991 Sunsport. I have had it about 5 years now and it has less than 300 hrs. For some reason this year it seems I am using twice the gas I have in previous years. The boat seems to be running fine. The only thing I have noticed that I haven't before is a little white smoke coming from the exhaust. Any suggestions?

when was the last time you did a tune-up?

[saltare inverts]

SunsportMikeyD, I telling ya, 572cubic inches.

[supragriff]

Last tune up was about two summers ago.

[Salty87]

did you check the power valve?

there's only so many things that could cause this.

is the hull bottom clean? prop?

tune up will only help. carrying any extra weight?...do you keep it covered? has the wake gotten bigger?

[wotan2525]

Yes and no. You can try a leakdown test. Get you a compression test gauge from the autoparts store, remove your spark plugs and the plug wire running from the coil to the dist. Then screw the guage in each cylinder and spin the motor over to see what the compression is on each cylinder. If the rings are in decent shape they will hold pressure if not they will leak down not instantly but over x amount of time. Also if you vary a certain amount compression from one cylinder to the next it is pretty much time for a rebuild.

Example if the compression on the #1 was 135psi and #2 was 85psi and the rest of them are 125ish to 135ish that would tell you #2 is suspect maybe a bad cylinder, bad rings or that cylinder needs valve work. Lots of varables. Most important you want the compression to be pretty even or close across the board.

This is actually a compression test. A leak-down test is similar but involves using an air compressor to fill the cylinder with air and then measuring how fast it leaks out (and where.) This will tell you where the air is escaping and give you a much better idea of what exactly is wrong.

Mikey -- How many hours on the engine? I'm sure you don't want to hear this but it does sound like rings.... and that means an engine rebuild. :(

[Hematoma]

This is actually a compression test. A leak-down test is similar but involves using an air compressor to fill the cylinder with air and then measuring how fast it leaks out (and where.) This will tell you where the air is escaping and give you a much better idea of what exactly is wrong.

Mikey -- How many hours on the engine? I'm sure you don't want to hear this but it does sound like rings.... and that means an engine rebuild. :(It works both ways actually. Either way your still compressing air in the cylinder. After more thought a leakdown will help you with a bad valve seat more than anything. Sorry for the brain fart I was in a hurry when I typed it. Mikey which ever way you choose, it can tell you what kinda shape your piston ring/cylinder walls are in.

[Hematoma]

And heres an FYI on the power valve on Holley carbs. You can check it by starting your engine and screwing in you air mixture screw. If the motor chokes and dies you power valve is fine. If it stays running you prolly have a hole in the power valve. Also all Holly carbs after 1992 have an anti backfire circuit to prevent the power valve from being damage from a carb backfire. When I say backfire I'm not talking about thru the exhaust but thru the carb. Just so there is no confusion.