Evinrude 18 hp Fastwin: Water pumping, then not pumping ...

[zul]

Then getting hot, so I shut it down. I've just spent the day with my mechanic, we replaced some seals, o-rings and a new water pump.

After starting, when I twist the throttle, the motor won't rev up. If I reach inside the motor, I can throttle it up with the arm extending off the carb. That keeps it reving and running. But not from the tiller arm??

Next, I watch for water. Sometimes, water is coming out, other times, no water. It's on and off again. Minute by minute.

In the few minutes where I had it running, I did get it into gear, forward and reverse. Seems to be shifting fine.

Water pump: it should 'work' or 'not work'. Why sometimes and not others?

 

[racerone]

Model # is ?------Head bolts tight ?------ Compression tested ?-------Thermostat checked ?------Is the pump fully submerged in your test bucket ?----Water must be 6" above the pump.------Motor must be in gear to go to full throttle.-----Are you sure it is running on both cylinders ?-----Does the motor have 2 replacement ignition coils or are they still originals?

 

[zul]

Model # is ?------ 18702R - E 07895 from 1967

Head bolts tight ?------ Yes.
Compression tested ?------- 100psi, both sides on a dry comp test.
Thermostat checked ?------ No. I don't know how to do that?
Is the pump fully submerged in your test bucket ?---- I think so, I'm not 100% certain where the high water intake is?
Water must be 6" above the pump.------ I'll elevate my trash can, this will help.
Motor must be in gear to go to full throttle.----- Got it.
Are you sure it is running on both cylinders ?----- Yes, fairly certain as it sounds good and comp test was even.
Does the motor have 2 replacement ignition coils or are they still originals? --- Most likely original coils. Haven't dug that deep yet.

Problem is, it takes more than a 1 hour drive to get to a test lake. Trying greatly to not waste a day and hurt this motor!! I'm concerned that the water pump might not work properly and overheat the engine. I will verify the water level in my trash can and elevate the tank and fill, fill, fill to be certain. And report back ....

I would hate to drive to the lake tomorrow and overheat. Anything advise to avoid an overheat is greatly appreciated!!

 

[racerone]

Water in the bucket must be 6" above the PUMP.------Three wee bolts on top of cylinder head to find the thermostat.----Put in boiling water to see if it opens.------Remove flywheel and inspect the 2 coils.------No point going to the lake if you feel coils might be original.

 

[zul]

Even worse. Went to the lake and spun prop shaft. This boat and motor never made it onto plane. I am into this motor for $600 with new seals and water pump .... it wont propel.

What is the average cost of fixing a spun prop shaft?

This is not fun, at all.

thx.

 

[racerone]

Maybe 29 cents for a shear pin ??

 

[BlackoutBill21]

Make sure the tiny hole in the water pump housing is clear and not clogged.

also I had the same motor that had the same problem. Would rev up 100% until I popped the cowing and used my finger to pull the throttle. I also had a water pumping issue. Turns out my cylinder walls were shot and water was half going through the block and it lead to a cylinder wall blow out.

I would do the easy stuff first. Check pump housing, coils, shear pin then pull the head and check for clogs. Worse case pop off the power head (not difficult) and check to make sure that plastic piece isn’t melted and blocking water passages.

 

[zul]

Water is pumping now, user error on that one.

When I was on the lake at low throttle, the motor would buck about every 20 seconds or so. At first, it only kicked/bucked at low-throttle. Any idea what that could have been? Test run was all of about 20 minutes total ... and it seemed to get worse and started to kick at mid throttle, then the prop reved and spun.

Compression test before the lake was 100 psi, both cylinders.

I will check the shear pin, if it is the pin, that would be the first stroke of luck on this whole project.

But still wonder on the prop hub rebuild cost? My mechanic and I have put a lot into this motor. Is it worth spending the money to rebuild the hub? After the hub, I'll still have to deal with that bucking issue.

 

[racerone]

Well it might be jumping out of gear !!-----A clutch dog / gear wear issue.-----Or an adjustment issue.-----Your mechanic will know what to do.-----Lots of good used parts are available for that motor.-----New update forward gear price will shock you.----These are wonderful motors to own / use and maintain.----But if you have to pay a mechanic for the work you might consider a new " push the button and go " type of motor.

 

[BlackoutBill21]

this is the link for my YouTube video that shows what the motor looks like when it skips Out of gear due to a worn clutch dog. Just fast forward to about 2minutes and you’ll see the motor jump. Is that like what yours is doing?

https://youtu.be/pGIATay2azU

 

[zul]

Like the video, Yes, but no grinding. Just one small kick every so often. Is there some adjustment possible? Like the shift cable or desemble and re-assemble those gears? Probably needs to be inspected to really see the condition. It kicked like that 6 or 7 times total.

 

[BlackoutBill21]

Only fix that I know of is to either get a new clutch dog, gears, or you can flip the clutch dog around and see if you get lucky

 

[zul]

My mechanic (and the guy that sold me this project) thinks it might be a problem in the linkage. Was slipping (kicking) and then eventually came apart and went outta gear. The motor thinks it's in gear but it's still in Neutral and let it rev. So rather than a spun hub it could be the linkage came apart?

I know nothing about the linkage and he can't get to it for a while. Is there any chance that I could dig into the linkage myself and check it out?

 

[54bobby]

try tying a string around the shifter and when in gear pull the string and hold it to put tension on the shifter. if it's the clutch dog you should be running ok as long as you're pulling on the cord, if you still have the problem.probably not the dog.