496HO riser is blistered - Overheated?
 

All,

Looking for some info. I just had my 26 Sonic winterized and the shop advised I needed a new impeller and water pump as the water was not pushing through on the Port side when they ran it to winterize it. I went to go look at it today and noticed the Port side paint is blistered on the header real bad. If they ran it just for a minute and no water went thorugh, would it blister that much from just that little bit of running in the shop? The Mechanic said they did not have it running very long at all and shut it down. I am having a hard time with what they are saying. They also had to replace the rubber exaust hose to the transom as that melted too.

Any info would be greatly appreciated.

They get pretty hot, pretty fast, but you get smoke and burning odor before damage is done. It only takes a few minutes, 3-5 to start to overheat. I'd say they weren't paying close attention.

Thanks for the info. Much appreciated. I am making them re paint the header. They tried making it seem like it was blistered when I dropped it off and it over heated when I last had her out. That definitely did not happen.

[QUOTE=26sonicmotion;3560581]Thanks for the info. Much appreciated. I am making them re paint the header.

I beleive, the manifolds are powder coated not painted...... powder coat holds up much better.

[QUOTE=45Tripps;3561453]Thanks for the info as to the possibility of powder coating. I finally got around to calling Merc and the representative there said that the risers are not powder coated. They are the Merc black paint. The place I had the Sonic winterized pulled the riser before they shrink wrapped so they could bead blast and paint over the winter. All they have to do is bolt that sucker on after they pull the shrink wrap off the Sonic in the spring.

Is it summer yet? Can't freaking take the snowmobile out since there is no snow. This stinks! lol!

Pete

I was thinking of the Gill manifolds. The 502 MPI manifolds were painted Merc Black. If you have a 496, cant speak about those, have no experience with them.

Here we go! Posted in November about the boat shop (where I was winterizing the Sonic) where they overheated my motor to determine if the impeller needed replacement and the paint blistered on the port riser (they were not paying attention)... They they removed it in the fall to paint in the spring... well they repainted the riser 2 weeks ago and reinstalled it along with a new exhaust hose from riser to the transom (they melted the original in the fall when the riser blistered). Took the Sonic out for the first time this past Saturday. I was not on the throttle more than 5 minutes, when bang! The port exhaust hose blew a hole in the top of it just after the riser. WTF! Thank god for duct tape to keep me running so I could get to 3 mile bay to hang out then head back for the day. I was definitley not WOT with that patch job, but it held up enough to keep me running for the day. Anyone have any suggestions as to why this woud have happened? I think they did not replace with a high performance exhaust hose as this one seems to flex a bit when pressure is applied to it. Also the hose is about 1/2 inch longer than the starboard hose. My starboard exhaust hose (original equipment) seems a lot more sturdy (no flex) than the one the shop placed on the port riser. Any thoughts? I called the shop Saturday after it happened to tell them about it. I am not sure I want that hack of a mechanic wrenching on my Sonic agian.

It sounds like you have pieces of the impeller in the sea water side of the exhaust which is causing the overheat. It needs to be disassembled and back flushed. Usually, it's best to try and account for all major pieces of the impeller by trying to match them up once all are popped out via backfluahing.

Thanks, Sydwayz. By disassembling, you mean the exhaust/riser on the port side where the issue seems to be, not the waterpump, correct?

Pete

Bad hose clamps
 

Attached are a couple of shots I took of my
riser problem last fall. The problem was
hose clamps that Mercury uses. One of them
corroded and popped of while I was running.
No alarm just a fire and smoke coming from
the engine compartment. All cooling water to
the riser went into the bilge so the riser quickly
over heated! I shut the engine down and the
fire stopped. What a mess. It took me four
hours to idle home on one engine. One thing
to Mercury's credit is that the closed cooling
system protected the engine from any damage.