Volvo Penta AQ145A (Fairline Weekender) ?? Blocked manifold

[topsyjones]

Hi - just wondered if anyone can help please?

Can sea water from the cooling system find its way into the exhaust manifold and therefore into the engine - either by blockage, corrosion or malfunction?

Also could anyone explain how the exhaust manifold works in conjunction with the water cooling?

As you've probably guessed I have water (a lot of it) pumping out of the carburettors and and wondering if it is coming from a blocked manifold.

Everything was fine then the engine suddenly cut out and I haven't been able to start it since. It is turning over but not firing up. On inspection found all of this water and not really sure where it is coming from.

Any help much appreciated.

 

[Bondo]

Re: Volvo Penta AQ145A (Fairline Weekender) ?? Blocked manifold

Ayuh,... Welcome Aboard,... I'd sooner think yer problem is a cracked or rusted through exhaust manifold,...

Pull it off, 'n inspect it,...

 

[captmello]

Re: Volvo Penta AQ145A (Fairline Weekender) ?? Blocked manifold

Go to this website and type AQ145A in the "engine type" box and hit search. from there you can download an owners manual which has a diagram of the cooling system.

Engine database - Engine database : Volvo Penta

Basically, because you have a fresh water cooling system (anti freeze in the block), the raw water comes from the outdrive, through the raw water pump, then it passes though a strainer, then through a heat exchanger which cools the antifreeze in the block. Then it goes through a oil cooler, then through the exhaust manifold, then out with the exhaust.

Because the manifold is water cooled, if it cracks from freezing or corrosion water can get into the engine. Is this a salt water boat?

If water is coming out of the carb, I would suspect a bad timing belt as well as a questionable manifold.

 

[topsyjones]

Re: Volvo Penta AQ145A (Fairline Weekender) ?? Blocked manifold

Hi - thanks for the help.

Full story short . . . .Yes this is a sea water cooled boat. Engine was running normally then I fitted an Acuspark electronic ignition kit. Engine seemed to run better after that. Re-tuned the carburettors. Went back to the boat after a couple of days - it started first time - ran perfectly for about 5 minutes - noticed a slight ticking/knocking from the outdrive while I was on the pontoon (sounded like a gear was partially engaged but it wasn't) Then I left it for a couple of days - went back and re-started it (ran fine for a couple of minutes then stopped so fast that I suspected fuel starvation or lack of a spark. Tried turning it over and over - slight misfire - kept trying but would not start. Took off air intake filters and turned over again - that's when about 6 foot of water erupted from each carburettor.

So I have taken your advice and removed the exhaust manifold & have washed all of the water from the cylinders, lubricated them, fitted new spark plugs. Tried to fire up but still no go.

Now I suspect damaged valves.

Also when I removed the exhaust manifold the water in the exhaust outlet was right up to the top and into the seal linking the manifold to the outlet. Do you know if the water level should be this high please?

I suspect blockage in the water exit in the outdrive. WHAT DO YOU THINK???

PS sorry it's such a long saga but it is really pi***ing me off - as a retired engineer I really should know this stuff

Very cold here in Wales

Send sausages

 

[dannys2004glastron175mx]

Re: Volvo Penta AQ145A (Fairline Weekender) ?? Blocked manifold

I would pull the manifold off and pressure check it first thing,

 

[captmello]

Re: Volvo Penta AQ145A (Fairline Weekender) ?? Blocked manifold

If water is coming out of the carb, I would suspect a bad timing belt as well as a questionable manifold.

Did you check this yet?

 

[topsyjones]

Re: Volvo Penta AQ145A (Fairline Weekender) ?? Blocked manifold

Hi - yes have taken off the manifold and will be pressure testing it tomorrow. Also checked the timing belt - seems all good.

Just wondered if there should be this amount of water in the outlet (SEE PHOTO) as a norm??

 

[topsyjones]

Re: Volvo Penta AQ145A (Fairline Weekender) ?? Blocked manifold



Here's another picture

 

[captmello]

Re: Volvo Penta AQ145A (Fairline Weekender) ?? Blocked manifold

Hi - yes have taken off the manifold and will be pressure testing it tomorrow. Also checked the timing belt - seems all good.

Just wondered if there should be this amount of water in the outlet (SEE PHOTO) as a norm??

View attachment 222575

No, not normal. The exhaust should drain. Do you have a 280 outdrive? Some 280s us an exhaust bellows with a built in flapper. I wonder if the flapper is plugging up the exhaust. or the bellows is backwards...

I'm still wondering about the timing belt. How else would the engine pump water out the carb?

 

[Maclin]

Re: Volvo Penta AQ145A (Fairline Weekender) ?? Blocked manifold

View attachment 222576

Here's another picture

Was the boat in the water when this pic was taken?