Gas in Exhaust??

[ldweber51]

Greetings. I have a 86' Bayliner with 2 volvo 260's with points & carbs. Recently I started to notice that after cruising for an hour or more, I notice a gas slick behind the stern.<br /><br />I do not have this problem when I leave the marina.<br /><br />I assume that gas is coming thru the exhaust because there is no eveidence anywhere else.<br /><br />Plus I believe I using more gas than normal.<br /><br />Any info on what maybe causing this would be appreciated. Thanks. Larry...

 

[shadowdwpp]

Re: Gas in Exhaust??

check your flame arrestor make sure it allows sufficient air intake could help with unburned fuel. Check your bilge and see if there is fuel in it. possibly replace the fuel filter if water is mixing with your fuel it would cause a higher compression rate and would make it less likely for the fuel to combust thus it would leave through the exhaust. Also if you are not a mechanic take it in to get serviced a boat is the last place you want to be dealing with fuels spills and others on the water will appreciate not having to tube, ski or fish in gasoline slicks.

 

[shadowdwpp]

Re: Gas in Exhaust??

check your flame arrestor make sure it allows sufficient air intake could help with unburned fuel. Check your bilge and see if there is fuel in it. possibly replace the fuel filter if water is mixing with your fuel it would cause a higher compression rate and would make it less likely for the fuel to combust thus it would leave through the exhaust. Also if you are not a mechanic take it in to get serviced a boat is the last place you want to be dealing with fuels spills and others on the water will appreciate not having to tube, ski or fish in gasoline slicks.

 

[ldweber51]

Re: Gas in Exhaust??

flame arrestor were both cleaned. I replaced plugs,points, condensers, rotors & caps. Wires were new. No gas or fumes in the bilge, I am not sure when fuel filter\separators were last replaced. Will replace both. I did not notice any water in the fuel on 1 engine when & replaced the needle & seat. Not sure on the other engine. Thanks for the info! Larry...

 

[Kiwi Phil]

Re: Gas in Exhaust??

Please accept the fact I am a mechanical idiot. my knowledge is zero.....but i have just had a problem similar to your's solved. <br />Whenever i stopped the boat, we would notice what we believed to be petrol, on the surface, at the stern. It would just appear, spread /fan out, then drift off with the tide. It did this continually, for months.<br />Then the other day my trim tabs refused to work.<br />Got the mechanic to take a look. No fluid left in the trim tab resoviour. 30 seconds later he tell me the hose to the starboard tab is loose. Then found the clamp had rusted through. So after new clamp, new fluid, everything is perfect, except he got pretty wet doing up the new clamp as the boat is permanently moored.<br />This is probably way off the mark with your question, but the initial symptoms seemed similar.<br />Cheers<br />Phillip

 

[vinney]

Re: Gas in Exhaust??

Trim tabs leaking or the power steering cooler leaking to the water hose.

 

[ldweber51]

Re: Gas in Exhaust??

Thanks for the tips. I do have a small leak on the hydraulic stern cylinder that I already knew about, but what is happening does have the gas smell, so I'll check my fuel filters & see if all the new plugs are indeed firing. Larry...

 

[ldweber51]

Re: Gas in Exhaust??

Greetings, plugs & fuel filters looked ok, still have some gas coming out the exhaust.<br /><br />I have noticed that both engines run at different temps. My port runs around 150 degrees & my starboard at 130 degrees. The gauges are new.<br /><br />On these OMC\Volvo engines, what is the normal temp?? Can incorrect temp cause excess gas in the exhaust/td>3F<br /><br />Thanks for your help. Larry...

 

[Skipster1]

Re: Gas in Exhaust??

Have you considered the possibility that the gas mixture is simply set too rich?<br />I don't know Volvo engines but I do know basic gas engines and it sounds like you need to lean out the gas mixture????

 

[ldweber51]

Re: Gas in Exhaust??

Yes I have, they mixture screws are only out about 1 1\2 turns, any closer in than that then the engine stalls all the time. <br /><br />Thanks for your response. Larry...