This page discusses the common problems found with marine
EXHAUST MANIFOLDS !!
If you arrived here from the main page, did you guess right??,
IF THIS IS THE CASE DO NOT CONTINUE TO RUN YOUR ENGINE (IF IT WILL).
it happens is this,
at this point you are still running the engine, when you switch off there
is good potential for the water remaining in the manifolds to run straight
into the exhaust ports (no exhaust pressure now) and fill the cylinders.
IF AN ENGINE IS LEFT IN THIS CONDITION FOR MORE THAN A SHORT LENGTH OF TIME CORROSION SETS IN RAPIDLY ON ALL INTERNAL WORKING SURFACES AND A TOTAL REBUILD WILL BE NECESSARY.
ENGINES LEFT FOR MORE THAN A FEW DAYS WILL START TO GET RUST GROWING ON THE VALVE STEMS AND EVEN IF THE ENGINE TURNS OVER THE VALVES MAY NOT RETRACT PROPERLY AND COULD COME INTO CONTACT WITH THE PISTONS.
BE VERY CAREFUL WHEN ATTEMPTING TO TURN OVER AN ENGINE WHICH HAS HAD WATER INGRESS AND BEEN LEFT FOR A WHILE, THIS SHOULD BE DONE BY TURNING THE CRANK WITH A WRENCH AND WATCHING THE VALVES.
DO NOT USE THE STARTER UNTIL IT HAS BEEN ASSESSED THAT EVERYTHING IS ROTATING AND CLEARING OK
If You have an engine full of emulsified oil please call for advice, do not attempt to just drain and refill it !!
The Bottom line is this,
If the boat has been used in salt water from new and your Manifolds and Risers are 10-12 years old or older you should consider replacing them ASAP, and if they are older still than that then you are on borrowed time, we have seen manifolds that have reached 15-18 years but it may be that the boat has spent some of its life in fresh water.
Fresh water is nowhere near as corrosive as salt water and Manifolds can last for years and years in fresh water.
Now that you're all scared to death, you may simply have a misfire caused by a plug or lead or dirty fuel, but if you suspect water ingress pull out all the plugs and look at them, if there is any debris or deposits on any of them it is probably salt and would be salty to the taste, however we cannot recommend licking spark plugs but that is up to you, ( I quite like 'em)
These water ingress problems can also be caused by a --
However any of these causes are rare compared to Exhaust Manifold Failure.
If you Need advice or are unsure about your symptoms call us now on
are UK Distributors for Osco and GLM replacement Manifolds and risers