12 yr old risers

N

njsr2002

New Member
Jul 3, 2011
30
NorthEast
Boat Info
2002
Engines
4.3 liter MPI Mercruisers. Alpha, Gen II
I believe my boat has the original risers and manifolds- it's a 2002 Searay Sundancer. I've kept it in salt water the past 3 seasons, original owner kept it in fresh water. I pulled the exhaust boots off the riser ends to take a peek and there is still a lot of Iron them, and I've had no overheating issues. But from all I've read 12 yrs is a very long time to let them go. A leak can occur at any time with no warning, and it can ruin my engines. I think if I spend any money on upkeep this spring I gotta do the manifiolds/risers.

This make sense to you veteran boat owners ?? or am I being a worry-wort ??

Thanks
 
Change them this year they are way over due. Go to Marine Power up in Wall by ariport he get them in in truck loads and has best prices by several hundred.
 
I think you're being realistic. One of mine went last year with no warning, I plan on doing the other engine this summer.
 
I just finished installing them yesterday. Not to bad. twin 5.7s Now I am cleaning the thermostat housings so I know they are good. Did the circulation pumps also
 
My 1994 300 sundancer with +/-750 hrs is still running original (freshwater) 2007 240 sundeck had them changed at around 350 hrs (saltwater)
 
Thanks for the reply. Was there anything tricky about removing all the stuff that's attached to the risers ?? (ECM brackets, shift bracket, etc) ? Do you just remove the 4 bracket bolts and lean it all over to the side ?? Thanks
 
Our first boat was a 1982. It had 600 hours on it when I got it in 2000 I had the risers replaced when the engines had 1000 hours on them in 2003. The mechanics comment was "Boy were you lucky" Now I know what he ment. I would replace yours if I was you. I have done the boat we have once. You can take them off after a few years and take them to a rad shop they can clean them and you can see if there is corrosion damage. I used OEM parts they fit well and all ou need is beer and a few strong friends.
 
WOW, 12 years:) In salt water they reckon 5-7 years. We're just having ours changed and the mechanic said the rust in the manifolds was really heavy duty. S/S Risers were okay thank goodness:)
 
The bracket for cables i tied off across to hold them out of the way. For the manifold install, i cut the head off 2 of the old bolts the grinded a slot in the tip to make it a screw driver so i can twist them out . Just put the two non head bolts on the farthest sides then slip gasket and then new manifold on, put on the new center bolts first them pull out placement bolts and continue
 
Doing mine this next week or so when the parts come in. Took the port manifold off to investigate what caused a bit of rust on the plugs in cylinders 5&7 The joints between the manifold, riser, and elbow were quite corroded. Found the PO or mechanic had installed 2 mainfold gaskets between head and manifold, can't follow the logic behind that one as there was evidence of exhaust gases degrading the area between the gaskets.
 
1990-270-da-lover said:
Doing mine this next week or so when the parts come in. Took the port manifold off to investigate what caused a bit of rust on the plugs in cylinders 5&7 The joints between the manifold, riser, and elbow were quite corroded. Found the PO or mechanic had installed 2 mainfold gaskets between head and manifold, can't follow the logic behind that one as there was evidence of exhaust gases degrading the area between the gaskets.
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When I bought my boat last year, I had them replace the manifolds/risers as a condition of the sale. Unfortunately, I didn't think it through quite far enough - they put the new parts on, but didn't tell me that the heads were corroded/pitted and just put a ton of RTV in there. When my mechanic was winterizing he noticed a major exhaust leak on the starboard motor, and a leak-down test of the port showed some major issues as well.

Currently having the heads milled, valve-job, and anything else they can find wrong taken care of on both engines. Expensive lesson, but at least I'll have some nice solid engines when he's done.
 
Had anybody ever changed over to stainless manifolds risers blocks and elbows? I know there more money but I also heard there indestructible. And last a lifetime. .. I'm worried about cast to stainless I know there's a gasket but did that matter? And if so were did u get them? I'm fwc with raw water inside the manifolds
 
src said:
When I bought my boat last year, I had them replace the manifolds/risers as a condition of the sale. Unfortunately, I didn't think it through quite far enough - they put the new parts on, but didn't tell me that the heads were corroded/pitted and just put a ton of RTV in there. When my mechanic was winterizing he noticed a major exhaust leak on the starboard motor, and a leak-down test of the port showed some major issues as well.

Currently having the heads milled, valve-job, and anything else they can find wrong taken care of on both engines. Expensive lesson, but at least I'll have some nice solid engines when he's done.
Click to expand...

The head connection looks OK with the exception of some gasket material stuck to the seat. I am going to lightly sand the seats and make sure all the old material is removed and proceed with "1" gasket and proper torque spec of 25 ft lbs. obeying the tighening guidelines and see what happens. fingers crossed LOL.
 
I am new to having my 2000 310 da. I have 350 hrs on 5.7 horizons. How would I know if risers need replacing?
 
Boston-boater said:
I am new to having my 2000 310 da. I have 350 hrs on 5.7 horizons. How would I know if risers need replacing?
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I would pull them off and take a look at them. Cost of time+gaskets, but at least you will know the true condition.
 
Thanks. Does it make a difference that the engines are FWC? What would be an estimate for time to pull the risers? Thanks.
 
Just finished up the entire manifold/riser/elbow project yesterday. All new hoses and fittings, new thermostat housing/thermostat. Wasn't as bad as I thought getting the manifolds back on, fashioned a wood handle that I drilled out to fit diagonally across the riser opening in the top of the manifold and used 2 3/8" bolts that came with the manifold, but that I didn't need, to fasten the handle to the mainfold, then I could hold it with 1 hand while starting 2 of the long 3/8" bolts to keep everything lined up, then just slid the manifold up into place and started 2 of the proper bolts in the ends, drew up the manifold just tight and put in the rest of the bolts before torquing all to spec. The rest was easy. It was definitely time to do the manifolds because there was evidence of water beginning to leak into both sides through the riser connections.
 
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