i took my boat out yesterday for the first time, it started fine when i first got her in the water and ran for about 5 minutes.. but then i heard an alarm sound (a constant, high pitched buzz coming from the throttle box) so i took her back to the boat ramp and cut her off; then she didn't start again... the prior owner said she flooded; i squeezed the hand pump for the gas quite a few times (when trying to start her up again) as well as pulling up the choke lever (the "lift toggle for full choke" lever, which also says "lift to warm") every time i tried starting it which was quite a few times... any ideas? also, does that choke lever actually cause gas to go into the engine and therefore i shouldnt pull it up every time i try to start the motor? i'm a little confused on that

I'm assuming this engine is not oil injected. If not, the high pitch alarm was most likely over-heating.

On a 78 model Rude. That horn has NOTHING, I MEAN NOTHING to do with flooding. It is used as a warning, to let you know that the engine is OVERHEATING. Bad JU-JU. It needs an impeller NOW!And at the outside chance a thermostat.
As far a choking the engine each time, You should not have to do that once the engine has been run. Maybe, only Maybe you might need to raise the fast leaver to quicken the starting. If your having to choke the engine, You have other issues that needs to be addressed by a quilified mechanic.

floats are sticking

how difficult would it be to install a new impeller (or thermostat)? i'm new to boats but i've done a little maintenance stuff on cars... also, is there supposed to be water shooting out of the spray hole on the side of the back of the boat when it runs? because when i ran it, i didn't see any shooting water...

Yes, there should be water, more so at idle than at WOT (the hole is called the idle relief hole)...If it's not, that's a sign the water impellar, if not the entire water pump, needs to be changed...The impellar on most lower units cost about $30.00, the entire water pump runs about $50.00...They aren't that difficult to change out...But you probably would need some help and I'd purchase a repair/maintenance guide...

i'm glad i read this thread cause my motor is having similar issues with that sound from the throttle control box.

and it's nearly impossible to start without ether

gambit, what's your motor? same constant alarm buzz sound that keeps sounding?... keep in contact in case you find a fix, and i'll do the same....

i think i'll try to get her out in the water and into idle in order to check water spray from that idle relief hole first; (if it ain't working, i'll get a new impeller after i get a manual)... if i hear the alarm, i'll do the same... and hopefully i won't flood it again.... i won't get her out in the water until sunday sept 7th but i'll post back my results...

oh, and thanks for the help everybody! much appreciated!

it's a 1974 85 horse evinrude, it only makes the sound in reverse and in the first third of the reverse throttle quadrant

buddy of mine just found a shop manual for mine

evinrude / johnson
outboard shop manual
48-235 HP 1973-1990 (includes sea drives)

at eagle marine in fort worth

If you are not familiar with removal of the lower unit and how to replace the W/P, do yourself a favor and get someone experienced to help. You'll save yourself a bunch of headaches and possible extra damage to the motor by messing something up.

The "warm-up lever" is just a warm-up lever, not a choke. It mostly advances the spark -- the throttles don't open until it's about 75% of the way up and in the full up position it only opens the throttles just a little bit.

If she's prone to flooding, a carb rebuild with new float valve needles & seats will usually fix it.

Some of those johnnyrude V-4's were made without telltales, but if it has one the outlet is a small nipple on the lower aft starboard side of the cowling and you should see a good stiff pee stream coming out there any time the motor's running. The relief ports on back of the motor just under the powerhead down't always have water coming out, and almost never when it's running on the muffs.

If you've been in the habit of cranking the engine without supplying water to the lower unit, that's the reason for your impeller damage...only takes about half a minute of dry running.

Water pump replacement, most 70's and 80's (maybe into the 90's) johnnyrude 3 and 4 and maybe 6-cylinder motors (take the prop off first):
1. disconnect shift linkage under the bottom carb.
2. remove the trim tab (scribe a mark across the edge so you can get it back like it was).
3. remove the retaining bolt up in the trim tab cavity.
4. remove the other retaining bolt from the bottom side of the antiventilation plate.
5. remove the four retaining bolts from the perimeter, just above the antiventilation plate.
6. pull the lower unit off.

the shift rod height is adjusted by screwing it in or out, so don't twist it or else it won't fit when you put it back.

7. There's a grommet around the driveshaft, and one for the water tube - don't forget those.
8. Four hex-head screws hold the water pump housing down.
9. Slide the old impeller off the drive shaft.
10. Slide the new one on. Slip the woodruff key in place just before the impeller covers the keyway.
11. Put a new housing gasket in place.
12. Grease the inside of the housing (trailer axle grease is fine), and shove it down onto the impeller while turning the driveshaft clockwise with your hand. Don't use any kind of tool on the driveshaft splines.
13. Fasten the housing back on.

On reassembly:
* put molly lube on the drive shaft splines (but not on top, there's not enough clearance).
* the rubber o-ring just below the drive shaft splines -- you need that.
* put omc gasket sealant (or some kind of anti-sieze) on the retaining bolts -- or else corrosion will set in & it'll be a bitch next time.
* use 3m #847 or permatex #2 on the joint between midsection & lower unit. www.ishopmarine.com has 847 -- permatex is way harder to clean off there next time around.

how much would all of this this cost in terms of labor??

this morning my dad, neighbor, and I did some more stuff: my dad found a small piece of broken rubber lodged into the bottom hole of the four breathing holes on the lower unit, which we quickly picked outta there (maybe it was blocking water flow?)...

then we hooked up a motor flusher (bought at wal-mart, five bucks) to see if water will flow thru the cooling system and engine; we found a blocked/clogged line, a short 6 inch hose runs from the engine block to the back of the boat where it sprays out of the little "pee hole"; the hose had small chopped up rubber pieces (maybe the same rubber that came out of the breathing hole???) that blocked the line so we cleaned that out; with the motor flusher on the engine, we ran some water and started the motor which ran fine and shot out a healthy stream of water for about 4-5 minutes before we heard that same darn alarm (constant buzz, presumably indicating overheating) once again so we shut her off...

honestly, i think the water pump works, maybe not full blast, but the water was definitely going thru the engine at a healthy rate... not sure where to go from here

The water pump could be working, but not to the optimum level...The blades on the impellar will bend, and sometimes melt and crack, over time, thus reducing it's performance...The buzzer you're hearing is a warning so that damage isn't done...

right.. but is it possible that i go to the shop, have the water pump and impeller replaced, and the overheat alarm still sounds??? what else might the problem be???.... if i can figure out where the thermostat is on this boat, i can change that at cheap cost and eliminate that as a possibility, but i can't find it anywhere

I don't know that particular powerhead well enough to tell you that...I can get the answer from my mechanic and look at your engine and we can change the impellar, but it will have to be Tuesday or Wednesday (my mechanic's shop is closed on Monday)...

It could also be a wire with a short in it coming off the buzzer...

Okay, there should be 2 thermostats...Here is the best diagram I can find to show you where they are...They are going to be at the bottom of the powerhead, but at the top of the exhaust housing (if that makes sense)...You'll have to click on the year for your engine and then the hp and finally the model...The number you are looking for in the diagram is 78...Once you zoom in, it's on the top left of the picture...I hope this helps and if you want some assistance, just let me know...

Diagram

theres lots of things that affect the pump other than the impeller, thr grommett in the cap must be in place abd in good shape, if the base plate is all dished out from wear this too can affect the pump , as i said in my pm put a new entire pump kit in not just the impeller and never crank it over dry

Since the pump is in question, I'd change it out anyway.

You can change out that water pump yourself if you're 1/2 way handy with tools. Write down you model number and serial number, then go to the dealer and buy a COMPLETE water pump KIT with the stainless steel base. Last time I priced it, it was about $50...but I'm sure it's higher now. Get a service manual too and you're good to go. Just PAY attention to the shift shaft. Read about it FIRST ! If it's like mine, that shift shaft bolt under the carbs is a pain the first time you try it. But it gets easier.

Jtexas gave a good description of the operation.

That piece of rubber hose in the intake is interesting. Are the screens still in place too? If not, there's no telling what kind of obstructions are in there.

Just because you have a good stream from the peehole on the muffs does not mean the pump is working properly. Remember the water thru the muffs is under pressure from the hose not nessessarily pressurized by the pump as would be on the water. Have and aftermarket service manual. Will be on Lake worth Sunday in the A.M. If You want to drop by. Call 817 677 5838 and I'll come in to meet at casino beach ramp.

oldfrog, actually no the filter-screen is not in place on the left side of the motor (from looking at motor from the back side); i need to install some of that screen, also; i have a roll of small metallic fencing stuff that might just work; do you think that, once i take the lower unit apart so as to install the water pump, i will be able to install the screen at the same time?

lonestar, i tried to view your diagram, but within which system will the thermostat be?
-CARBURETOR
-CRANKSHAFT AND PISTON
-CYLINDER AND CRANKCASE
-ELECTRIC STARTER PRESTOLITE MODELS MGL-4109
-ELECTRIC STARTER & SOLENOID AMERICAN BOSCH 10629-23-M03
-EXHAUST HOUSING
-FUEL PUMP
-FUEL TANK - 6 GALLON
-GEARCASE
-IGNITION SYSTEM
-INTAKE MANIFOLD
-MOTOR COVER
-POWER TILT AND TRIM
-REMOTE CONTROL????????????????????????????????????????????

the pieces of rubber are probably bits and pieces of the impeller that has come apart and worked their way through the cooling system.. never run an outboard without water to the pump.. when you run one dry the rubber impeller gets very hot and melts then sticks to the metal inside the pump... the next time you turn the engine over it tears the flippers off the impeller and starts pumping the pieces through the cooling system.. you will need a shop manual to understand the cooling system on your engine.. by all means replace the water intake screens while you are doing the water pump,both of them.. it takes less than a minute to dry run a pump and ruin it... hard starting/ poor idling on the old john/rudes is almost always carb and sync/link related if you have good spark..good luck and hope you get it going....

is this manual -- http://www.repairmanual.com/marine/2/445 -- the correct one for a 1978 Evinrude 115hp???????