Mecruiser 3.0L Hissing Sound

[SpringVelocity]

I took out my boat in some pretty cold weather over holidays. I am now getting a hissing sound when running...

My guess is its a exhaust leak somewhere... Anyone had same thing..My thought is its gasket in manifold.... I am also now having a tough time keeping it idle.... Starts up fine but wants to stall at idle... Sound is definitely coming from manifold side...

 

[trophy fisher]

Sounds like a vacuum leak at the intake manifold. An exhaust leak would not be a whistle noise but a popping noise.

 

[wolf]

With it being this cold out doesnt matter if its a inboard or outboard get it warmed up for about 5 mins then turn the engines off. as the engines start to run rough as its a term called "icing" cold air being sucked into carbs ..when you shut it down after warmed up for a bit the heat warms up the carbs.engine area etc.... set up all your stuff etc and you should be good to go...

The hissing could be the air being sucked into flame arrestor to carb ..1st thing to check is it completely clean?? you have to clean the air filter/arrestor every couple of months as the oil can really build up on them and restrict the flow for air getting to the Carb..

hope that helps Jerrod

good luck Wolf

 

[trophywife]

Yes, the icing in the intake can act like a choke, causing the rough/stall at low rpm..

 

[SpringVelocity]

With it being this cold out doesnt matter if its a inboard or outboard get it warmed up for about 5 mins then turn the engines off. as the engines start to run rough as its a term called "icing" cold air being sucked into carbs ..when you shut it down after warmed up for a bit the heat warms up the carbs.engine area etc.... set up all your stuff etc and you should be good to go...

The hissing could be the air being sucked into flame arrestor to carb ..1st thing to check is it completely clean?? you have to clean the air filter/arrestor every couple of months as the oil can really build up on them and restrict the flow for air getting to the Carb..

hope that helps Jerrod

good luck Wolf

OK I will check that Roy I never even thought about that....

Jerrod

 

[profisher]

Jerrod, try to keep the engine rpms as low as possible without stalling it out when it is cold. The faster you pull the cold winter air into the engine the quicker the ice forms. I had to start and stop my 2 stroke Yami 3 times on Friday before the block heat had radiated out to the carbs and the engine would run normal.

 

[Filletandrelease]

Jerrod, try to keep the engine rpms as low as possible without stalling it out when it is cold. The faster you pull the cold winter air into the engine the quicker the ice forms. I had to start and stop my 2 stroke Yami 3 times on Friday before the block heat had radiated out to the carbs and the engine would run normal.

Those 3.0's are notorious for vacuum leak from intake manifold gaskets.

 

[Califbill]

Spray carb cleaner around the manifold and see if it changes speed or sound. A water spray bottle would also work if worried about fire.

 

[profisher]

A vacuum gauge will work even better

 

[SpringVelocity]

Thanks guys I will check all these ....

 

[Califbill]

A vacuum gage tells you that you have a leak. The spray will localize the area of the leak. Sometimes only way to find a pinhole leak in a hose or gasket.

 

[SpringVelocity]

head gasket....instead of putting money in may replace with new motor..... just looking at options now..

 

[albernifisher]

Pod...

 

[IMRINC]

I have complete drop in mercruiser plus series 3.0l engine sitting in my showroom... Just saying

 

[albernifisher]

I have complete drop in mercruiser plus series 3.0l engine sitting in my showroom... Just saying

Chris, you probably have a couple big black outboards sitting there too...

 

[SpringVelocity]

Pod...

I so want one...but Its too much cash right now....

 

[SpringVelocity]

I have complete drop in mercruiser plus series 3.0l engine sitting in my showroom... Just saying

I see that a 3.0L TKS for $4400... I have one priced out with installation with mechanic 5k... maybe pm me..no decision yet. looking at all options.

 

[SpringVelocity]

getting replaced was lucky.....planed down and new head gasket just over 500.00....And I can put off new motor until beginning of summer.....Getting done this weekend...

 

[SpringVelocity]

Its fixed... Hissing sound was head gasket all tuned it up and ready to go...

 

[rockdog]

Right on.....