Two impellers fried

[jonsboat]

Bought 1991 25 HP Evinrude model VE25ELEID, was running it with water muffs on driveway to resolve idle issue and fuel leak when impeller quit and overheat buzzer sounded. Tell tale flow had been weak but steady. Outer impeller case was partly melted and impeller melted as well. Replaced, decided to run motor in 35 gal drum, good telltale flow. After 20 minutes of some higher rpms well above idle, impeller quit, same result. Am I running motor too hard out of the water? Or is the water in the tank too disrupted by exhaust out of prop to be sucked into head? Or do I maybe have a hot exhaust gas problem inside motor? Next run will be in the creek. Help!

[phillnjack]

ok first of all no running above 1500 unless on the boat in water or in a propertest tank with test wheel.
the water could be getting far too disturbed and a lot of air getting to
the inlets rather than free flowing water.
did you check to see if the water in the drum was hot ?

and when you repolaced the water pump impeller did you put a new bottom plate on and new gasket and make 100% sure of no obstructions below the impeller ?
next time pour water down the water pump and see if it flows out the leg quickly, if not then a blockage could be the problem.
the tell should be pretty strong when running in a water butt /drum.
poke a piece of welding wire or similar up that to dislodgeany spiders or wasps that love to get in there and stay warm,
( I have had loads of trouble with a Suzuki 30 with tiny spiders in the tell tale ).


phill

[jonsboat]

My Bad

I'm sure I exceeded 1500 rpms trying to keep the motor running. My friend who has been working on outboards for over 55 years told me the rpm wasn't a big factor and to check for something else. Didn't check the water temp during run, but it was barely warm when I emptied it some time after shutdown. Have checked tubing by reverse flow, but have not checked below impeller for blockage. Will look tonite.

[jonsboat]

Two impellers fried

Yes, I changed the bottom friction plate which came in the kit. Water intake is blocked with melted impeller rubber now, but was cleaned out before last ***embly. Had a strong indicator stream after start, should have paid more attention to it as I was working on boat and motor. The top side of the curved area of the long water tube is black where it bends just above the impeller case. Looks like exhaust carbon to me, figure it was the exhaust heat that melted the impeller? Or simply not enough water at high rpms?

[phillnjack]

your friend who has been messing up outboards for 55 years needs to leave them alone.
never run the engine at high revs on muffs, unless the fire brigade are supplying a huge high pressure to your engine.
plus you don't rev any engine high in neutral without a load.
that is simple schoolboy mechanic stuff you learn in the first lesson.
Now have you checked to make sure there is no crud between impeller and the inlets ? by you saying the exhaust has been leaking onto the water pump housing sounds like the thru exhaust is also blocked.
probably been run in weeds or mud. !!!!!
how warm is the tell tale when you have been revving this engine high ?
what temp is the engine block at ?
when you put the leg back on did you make sure the exhaust rubber seal was there and that the exhaust mating was perfect ?
to melt the water pump housing this has not had enough water to cool it for sure.

and just asking.. why rev it high if your trying to correct an idle issue ?

phill

[jonsboat]

Fried two impellers

Was running high rpms trying to keep motor going long enough to troubleshoot what I thought was a fuel supply problem. Put in new water pump kit, cleaned carb (idle jet blocked), cleaned primer hoses (blocked), and it worked well on water. My problem was self-induced due to inexperience. Started a new thread for occasional fuel starvation. Thank you for your candid inputs which have been followed.