25 hp evinrude query

[nthqld]

Hi all, just wondering if anybody has had experience with a 1986 25 evinrude.
I put the boat in today after it had been sitting for awhile,
got about a 200 yards from the ramp and noticed no water coming out of the tell tale.
Stopped the motor and tilted it up and I could hear a gurgling type noise coming
from the leg in the vicinty of the water pump.
Rowed back to the ramp :(
Dropped the leg and the impellor seems fine, might be the thermostat, will check it tomorrow.
The thing that has me alarmed is after the pump housing is removed you are able to
pull the drive shaft from the gearbox.
I raised it about an inch or so but didn't remove it as it doesn't seem right.
Would anybody know if this is how things are meant to be or has something failed?
What holds the drive shaft to the gear?
thanks for any help...
roger

[finga]

this may help
(http://www.crowleymarine.com/brp_parts/diagrams/28230.cfm)

[FNQCairns]

Those driveshafts do that, surprised me too, never had the gearbox apart so dont know any more about it. Only have minor experience having owned one for 8 years or so, only done basic stuff to it like impeller, sparkplugs, oil. Did it get hot easy to feel with your hand on the powerhead, I would put it back together again and run it, it will not overheat without getting hot to the touch, teletail will pump without the thermo opening, suspectthe pisser is blocked is all.

cheers fnq

[nthqld]

Thanks guys, the diagram was a great help.

Of course..tell tale would have to be bypass from the thermo...
when I have a think about it.

I was soo concerned about the drive shaft :)

The motor didn't seem to be overly hot, it was more the noise from the leg that concerned me as I haven't heard it do that before.

Felt the thermo and it was warm, but with hearing the strange noise I decided not to run the motor.

One things for sure, it has to be fixed :)
I'll let you know how it turns out.

thanks again

[FNQCairns]

Nthqld was the sound one that follows rpm, rattle/light knock, sounds like it comes from the midsection but hard to isolate just where, could be from where the impeller is but certainly doesn't sound lower than that, easily heard at idle, gone at high revs, a screwdriver isolates it as closer to the powerhead than lower?? hard to describe these things, anyway if that is the sound, you might want to check your not overproped and give it a good decarbon and some expensive oil for a while + a new prop (if I guessed right), heard it before on these engines, each one was over proped or getting a bit long in the tooth for whatever reason not just hours.

cheers fnq

[nthqld]

Hi, The sound was coming from the leg..around where the pump is after I stopped the motor and tilted it up.

I took the cowl off and checked to see if the powerhead was hot and it seemed ok, so I started it again to motor closer [50 yard run] to the bank to get out of the wind and strong current that was running against me..rowing sux :)

Tilted the motor and it made the gurgle sound again...doesn't usually do that.

$150 for a water pump kit in Cairns..how crazy is that!
I'll ring Hunts in Tully tomorrow as I haven't changed it for a few years and the blades have a lot of set..on them.

[FNQCairns]

Ok mate good luck, if it doesn't get hot to the touch it's not overheating (as you probably know) so in theory pumping ok. Yeah prices are certainly silly!!

I bought a prop for mine a full $100 cheaper from Hunts than I could in Cairns.

cheers fnq

[SunnyCoastMark]

Roger,
Check your tell tale for any obstruction - typically a mud potters wasp nest.

Very common ailment. Nine times out of ten - that what it is.Try poking a piece of wire up there.

Mark

[nthqld]

Hi all, the downdate well there is no up side to it :)

Fitted a "new" better condition used impellor last night with new base gasket.
The housing and base plate look ok, just a bit of wear.
I will be getting a new pump tomorrow.

Removed the water hose from the thermo to the tell tale and checked for blockage...none.

Hooked garden hose to water inlet pipe while the leg was off and there is a good flow out of the tell tale.

Cecked the lower water intake and passage... all clear.

Took for a run and all was good for about 300 yards then tell tale died.
Went to poke the tell tale with a bit of wire and steam was being pumped out,motor running.

Stopped motor, thermo too hot to touch, water cooling jacket too hot to touch,
cylinder head cool to the touch.

Waited 5 minutes and started motor and all was good for about..300 yards and then the same thing happened again.

With the motor stopped it still makes the gurgling sound for a couple of minutes.
any ideas what could be going on?

thanks roger :)

[FNQCairns]

My guess and it is a guess is the thermostat is stuck/corroded and is causing a hot spot which creates steam that just makes the situation worse, apart from that and a poor impeller/housing which may if it is, wouldn't help much.

The thermostat from memory is hard to pull on those, think it was under the head cover??

I would ensure that everything to do with the pump is in spec and good then try again, any doubt and it just complicates matters.

The faster you travel the less work the water pump has to do, water pressure does most of the cooling, but if you do that, gotta keep an eye on things and do a blat right from cold and stop before it has a chance to go overheat.


cheers fnq

[nthqld]

Yeah fnq I was thinking along the lines of a blown head gasket super heating the water but I'm not to sure of the water passage flow.

The tell tale is outlet from the water jacket before the thermostat.

Does the thermostat just restrict the water till it opens and then allows flow through it and then the water is dumped, allowing a greater flow of water through the water jacket than just the tell tale waste water?

If this is the case the thermo mustn't be opening and the water in the water jacket is being held back by the thermostat, boiling when the motor heats and being blown out the tell tale as steam.

Your right the thermostat is under the head cover :(

Do you have any idea of the flow passage of the water, how does the system work, where does the water flow after the thermostat?

thanks for your help :)

[FNQCairns]

The headgasket idea is a good thought if just to be done with it, these engines are known for corrosion at the bridge between cylinders, so yes certainly worth a compression check. Pull your plugs also and check for any that are very clean (or rusty).

Yeah, the thermostat on these is a heating aid more than a cooling aid, water should reach most places with it closed, but restricted, when it opens the volume of water increases through the engine per unit of time, too much volume for the drains at the base of the powerhead so it all fills up. Think of this engine being used in alaska, the thermo is hardly ever open at slow speed yet all of the hottest gallerys still get the water they need for common expansion, just less flow.

Not sure where the water goes after the thermostat on these on my 90 yam it dumps straight down the cylinder head then goes to drain I assume, I cannot remember if when flushing any new outlets started spitting water once the thermo opened like some larger engines do.

cheers fnq

[SunnyCoastMark]

Rog,
I had the same problem with my 1984 25 hp Johnno (same motor). Pull off the head cover, which will expose your thermostat - mine was stuffed.
I then went further - pulled off the head, replaced the head gasket.

I also stuck some wet and dry to a peice of glass and used that to resurface the head.

Put it back together - ran like a dream until I sold it.

It is a pretty easy job to do yourself.

Regards,

Mark

[Coontakinta]

Reckon, I have a similar problem with my 1996 25hp johnson. (thermostat trouble????) Plenty of cool / cold water from the teltale, but the that from the exhaust is hot and steaming. Impellor was my initial thought but although needing replacement was bad enough to be the problem. Am looking for the thermostat now????

Is it possible for corrosion / muck to be caught somewhere in the loop so as to stop sufficent water getting through or would this simply be a thermostat problem. This motor doesnt get a lot of use these days as I'm out in the big rig mostly, but sometimes take the tinnie out for shorter sourays or for bream'n.

[FNQCairns]

Coonta use your hand on the metal parts of the engine to confirm if it is indeed running hot in any particular place, I cannot think of an outboard a person couldnt leave their hand on when it is at idle if all is ok. Engines can gunk up and cause problems but only you know its history.

My 25 also steamed from there but only after a run, the good thing about the impeller is that replacing it is always a good idea when trying to diagnose a sticky problem (very often it is the impeller/case) even if it ends up not the cause the engine is in a better place and every other area worth checking can get complicated and costly when compared to a replacement impeller.

cheersfnq

[Coontakinta]

Thanks FNQ.
Plan on getting anew impellor, housing, and plate as the pla

te appears to scored slightly. (Not surprising I guess after 11 years!) Once I've done this I'll put back together and see, taking note of your comments. On another not hope to have some info on my prop problem soon. Plan on visiting the parents this week so if weather is favourable will take my rig along for some prop swapping and testing.

Many Thanks again

[nthqld]

Thanks Guys,

FNQ you were right on the money with the run down of the cooling system.

I removed the water cover and found a badly corroded thermostat which had broked in half.

I'd say this is causing my grief, haven't tested it yet as I'm still doing battle with a centre bolt that broke of flush with the head.

Removal of this cover, check thermostat and anti seize to the bolts should have been on my maintence routine..but it wasn't.

Thanks again for the helpful posts, I'll post when I test run