1988 15 HP Evinrude Wont Start or Idle when Hot

[luvmystang67]

I have a 1988 Evinrude 15 HP that typically runs extremely well. When I first picked it up probably 8 years ago it wouldn't cycle water. I ran a wire up the show hole and that didn't seem to fix anything. I then went about replacing the impeller. This was a while ago, but I'm pretty sure I also replaced the thermostat (not 100% on this). I did take it out to a lake and run around for about 5 minutes and it overheated and quit. (I was kind of hoping it'd clear itself, but it did not and I rowed in). Still didn't cycle water and I got upset and put it in storage. This is literally all the run time I have had on it.

I just pulled it out the other day and decided to take another crack at it. Fired it up just to make sure it still ran (it does and quite well, 2nd or 3rd pull). Still didn't cycle water. I took the air compressor and shot some air up into the water indicator hole...and out came the water! So I was super excited. I've never had run it for very long before so I took it out, happy as can be for a couple of laps around the lake. Probably ran it for 15-20 minutes straight. It idled great, turned it off and restarted it, great, everything was awesome.

I turned it off and floated for 10 minutes. Tried to start it back up and it would fire and sputter and then quit. Nothing I did would make it stay running. Finally I took the cowling off and manually over-rode the rev limiter for neutral and it fired up and ran fine at a high RPM, but as soon as I tried to bring it back down to a reasonable RPM to shift into gear it'd die or try to die. I finally got it in forward, headed back and turned it off one last time as I was coasting to the launch. It wouldn't restart.

I also noticed on my last lap around that when going full out, there was a little water coming from underneath the bottom of the engine cowling bowl (not sure what you call that but it was seeping down the leg... very slowly) and there was also water it appeared, that was leaking around the seal where the shift level goes into the lower unit or almost lower unit. This is a very small seal and it doesn't SEEM like this should be a big deal.

SO, what is my problem? Did it just get too hot? The water doesn't exactly jet out the indicator until I'm at full speed, at idle it sometimes just dribbles. The leg gets too hot to leave your hand on for more than about a second? Is my impeller likely bad even though its just been sitting (on land undercover)? Did I not replace a seal in the impeller area that I should have? Does this sound like it could be a thermostat issue (however I'm nearly certain I replaced that guy).

Help please... will these things run well at full out, but not idle, if they are a little too hot? That is what it seems like might be happening... Why is there water coming out the leg (up top and where the shift shaft goes in down low), is that a wet area or is it half sealed off?

Thanks in advance.

 

[Davem3]

Re: 1988 15 HP Evinrude Wont Start or Idle when Hot

impellers need changing every few years, they do DRY rot just sitting there.......... replace the whole pump, NOT just the impeller, the have a new SS insert that is the bomb.............while the LU is on the ground, use a air compressor on the the water pipe going to the head, look for blockage...............

back the the LU.......... drain the gearcase, look for water........... again use a air hose on it but with 3 PSI ONLY!!!!!!!!!!. set in one screw, use the open one for the air hose, that will check your seals, the one for the shifter, driveshaft, and behind the prop......... change the oil ( 85~90W gear oil) and change the screw seals as well..............

the idle problem sounds to me like a gummed up carb............ rebuild it and check the fuel lines , pump ball, and fuel pump as well........ethanol plays holy carp with this stuff..............also whenever you are done on the lake at the end of the day, after this, run it OUT of fuel before you put it back on the trailer, it will help out loads..........

finally NEW plugs and check for a good strong spark as well.............

good luck and see ya on the water soon ...................

Dave

 

[luvmystang67]

Re: 1988 15 HP Evinrude Wont Start or Idle when Hot

How come it idles and re-starts fine when it's cold or heating up and then when it's warm doesn't want to sit at idle? Is that really a gummed up carb? Just trying to keep this as least labor intensive as possible and get using it ASAP. Do I need to replace the thermostat if I'm doing the water pump?

Thanks

impellers need changing every few years, they do DRY rot just sitting there.......... replace the whole pump, NOT just the impeller, the have a new SS insert that is the bomb.............while the LU is on the ground, use a air compressor on the the water pipe going to the head, look for blockage...............

back the the LU.......... drain the gearcase, look for water........... again use a air hose on it but with 3 PSI ONLY!!!!!!!!!!. set in one screw, use the open one for the air hose, that will check your seals, the one for the shifter, driveshaft, and behind the prop......... change the oil ( 85~90W gear oil) and change the screw seals as well..............

the idle problem sounds to me like a gummed up carb............ rebuild it and check the fuel lines , pump ball, and fuel pump as well........ethanol plays holy carp with this stuff..............also whenever you are done on the lake at the end of the day, after this, run it OUT of fuel before you put it back on the trailer, it will help out loads..........

finally NEW plugs and check for a good strong spark as well.............

good luck and see ya on the water soon ...................

Dave

 

[Davem3]

Re: 1988 15 HP Evinrude Wont Start or Idle when Hot

How come it idles and re-starts fine when it's cold or heating up and then when it's warm doesn't want to sit at idle? Is that really a gummed up carb? Just trying to keep this as least labor intensive as possible and get using it ASAP. Do I need to replace the thermostat if I'm doing the water pump?

Thanks

that issue might be electrical, power packs/coils can be funny like that ............ i just figures go one step at a time to eliminate the problems from cheap to expensive ..............

also, some loose junk in the carb can do that as well............ sits at the bottom, then go into the jet nozzle ...........

 

[nphilbro]

Re: 1988 15 HP Evinrude Wont Start or Idle when Hot

I had this exact motor - and it's a great motor, but it's notorious for this problem.

You'll need to remove the power head starting with the 4? engine mount bolts with the rubber bushings. You'll need to remove the pull start and carb silencer as well so do that first since it makes it easier to access these bolts anyway.
Then remove the six bolts under the shroud that attach to the crankcase underneath. The two longer bolts go to the rear of the motor.
At this mount you should be able to pull the power head.

I removed the the lower unit when I did mine too. It seemed a lot easier with it off.

Now you can see the copper water tube as it enters the crankcase. There is a little P.O.S. rubber grommet that gets warm and melts over, or folds over, or wiggles over in a way that it completely blocks the water passage. On mine you could even hook that tube to a hose and it would spray out the tell-tale but it wouldn't suck any water from the pump.

Replace this grommet and reassemble. I swear I tried everything before pulling the head. It took me all evening but I got it back together and it started the next day and it ran cool. Reassembly isn't all that easy either so block out some time.

Good luck!

Edit: You'll probably need to get a new base gasket. I tried to reuse mine and it failed on the lake blasting exhaust out in front of the prop making me think I'd spun the prop but it was just extreme cavitation.