[peakay]

Hi there,

On our recently acquired 2700, the engine surveyor report indicated the risers need to be removed and re-gasketed (if not replaced) and the trans coolers were showing some concerning corrosion and should be replaced.

On the risers, indicated part # is 807988A03.  I assume on these parts we should stay Mercruiser OEM or is aftermarket OK? 

Since they are freshwater cooled, do you have to drain the whole cooling system or is it possible to just catch what spills out? I assume it is pretty straightforward, but any tips or tricks regarding how to do i is appreciated.

Thank you!

[Capt. Paul]

Hi peakay,
I did mine when I bought my 29 this year. I have Crusader 7.4 big block GM motors. The risers are salt water cooled but the Crusader exhaust manifolds are fresh water cooled. So I had to drain coolant out of the system before removing the risers/elbows or coolant would run into the exhaust gas side of the manifold and possibly into the cylinders.
Not sure if mercruiser has the same set up.
I have found on all the many boats I have owned, the engine manuals are worth twice the price, especially if you are interested in doing your own work.
Even if you don't do your own, it pays to be somewhat knowledgeable to keep from getting taken advantage of.
I would not be afraid to use after market parts from Barr or Sierra.
Regards,
Paul

[peakay]

Thanks Paul. I went ahead and shopped for the best price on OEM mercruiser risers and they shoudl get here within a week or so. I found a manual to download and unless I'm reading it wrong, the risers on this engine are also water cooled though I'm sure plenty of saltwater gets back up into the exists. The purchase survey recommended i lift the crossover tube slightly to prevent more saltwater getting in.

Hopefully I'll be able to give this a go before too long and without major problems that eat into the season too much. Scared to take it too far and risk water intrusion into the engine.