i spoke with "jersey joe" at length yesterday concerning his rig.i promised him i would show some pics of a late model volov engine that suffered severe damage from water intrusion-from the exhaust risers being eroded and pourous...
here they are...
this is a '02 engine,and this happened a few years ago.the engine was siezed,as in locked up.these engines used an exhaust recirc set up,this exhaust was redirected into the flame arrester-idea here was to reduce emissions.problem was,sea water was drawn into the engine-not good...
end result is rusted intake valves,and severe wear inside the cylinders due to rusting.this is why i preach replace manifolds and risers every 5yrs max,pull the plugs and compression test the engine every fall-this could've been avoided...too late now...i do not rebuild engines-ever.i do not use "reman" "long blocks","short blocks" or "partial engines".i repalce with new and new only,i use a "drop in" engine,i will not reuse parts from an old motor on a new motor... whatever it had in it,it gets replaced with,example,the boat had a volvo stern drive,it gets a volvo engine-i do not adapt-ever...this was replaced with a volvo 5.7gsi engine.

****here's a side note*** mercruiser engines,the new engires,vortec engines,these require a considerible amount more water volume than the old engines-that's the difference in the drives-alpha and alpha genII drives.the old alpha drives used a high pressure volume water pump,the new alpha gen II drives use a low pressure high volume water pump-where i'm going with this is,you can't use a new vortec engine from merc with an old alpha drive,the engine will blow head gaskets,due to the engine not getting a sufficient water flow...remember this if any of you guys are considering a repower with a merc alpha drive...

here's the pictures...


this picture shows the intake valve side of the head-note the rust in the intake ports ? note the rust in the manifolds as well...




the "white stuff" on the tops of the pistons,that's salt deposits,note the rust on the cylinders-clearly this engine has been ingesting sea water form a looooong time...




here's one of the cylinder heads...nice huh ?



you can see how clean the engine is..



this engine had under 200hrs on it...hrs are not a factor when it comes to failures from exhaust systems...this is the reason i preach inspections yearly...

Hey Jimmy,

I have a Volvo 2004 5.0 OSI-EF Stern drive. My engine is now 5 years old and it has 560 hrs. I pull and inspect my risers every season. I put new gaskets and check the mating surfaces. I run neutra-salt after every outing. I boat in salt but I dock way up a creek which is fresh water, I guess it is actually brackish. I will inspect my risers in the spring, even if they look good should I change out manifolds and risers?

What brand would you recommend Osco Barr Sierra OEM. The OEM kit is about a $1,000 and I think the aftermarket brands are about $450

Thanks in advance,
Jim

Just my two cents but I would go with Volvo manifolds and risers. There is a guy a few slips over that has older Volvo's and he goes through Osco's every other year...you get what you pay for.

Since we are on the topic of manifolds and risers...I will probably be doing mine next season. What are your thoughts on the Stainless Marine products Jim?

hey guys...just checked in...
personally,i use oem parts,nothing else...

i would not reccomend the stainless marine manifolds either.