Testing exhaust manifolds / risers / elbows (Mercruiser, probably others)

[thedillybar]

http://forums.iboats.com/showthread.php?p=1724605#post1724605

 

[Bondo]

Re: Testing exhaust manifolds / risers / elbows (Mercruiser, probably others)

I have an idea (haven't tried it) rather than removing exhaust manifolds/risers and pressure testing them.

(One side at a time)
Plumb the garden hose to the exhaust manifold (where raw water enters from T-stat housing). Turn the garden hose on w/o starting engine for 5-10 minutes.

Look through spark plug hole for water entering cylinders while hose is on.

Shut off hose. Check dipstick.

If you see water entering cylinders while hose is on, or you see a higher fluid level on the dipstick (with more water) then the manifold or riser or elbow is bad.

Not worth replacing individual parts if the damage is from normal, long-term wear & tear...replace manifold/riser/elbow on both sides.

Ayuh,..... Micky Mouse would be Very Proud of you.........

 

[joseph.signore]

Re: Testing exhaust manifolds / risers / elbows (Mercruiser, probably others)

What about the return hose on the bottom of the exhaust manifold... where dose that water go?

 

[Coors]

Re: Testing exhaust manifolds / risers / elbows (Mercruiser, probably others)

Search here for a manual

 

[joseph.signore]

Re: Testing exhaust manifolds / risers / elbows (Mercruiser, probably others)

Search here for a manual

Sorry. I don't understand. Search where for a manual. Where???

 

[Maclin]

Re: Testing exhaust manifolds / risers / elbows (Mercruiser, probably others)

Hey Dilly,

I vote BAD IDEA. For one thing it is not a good idea to TRY to get water to enter your engine under any circumstances. For another thing it is not a very valid test in my opinion. Water is not supposed to be under pressure and entering the exhaust manifold if the engine is not running. The water is supposed to be pushed up to the risers and mixed with the exhaust gas flow and blown on out with the exhaust. If you pump water into the manifolds while the engine is not running then on some (maybe all) configurations I would almost guarantee that water will enter the engine thru any open exhaust valves as the water hits the risers and has no exhaust pressure coaxing it on out of the riser and thus falls back down into the exhaust passages. So you have perfectly good manifolds and risers "failing" the test. Plus you now have water in some of the cylinders.