Evinrude 1976 9.9/15 - multiple failures, but could have been a lot worse

[Dabbler_E]

Hi All,

Sorry for the rant nature of this post, but yesterday was a pretty difficult day. Ultimately, I'm pretty sure that the fix will involve a complete carb teardown, but any more specific pointers would be helpful.

This is a motor I got on eBay last year as a 9.9 and installed 15 hp carbs (as well as replacing points & coils, replacing fuel lines, and adding a telltale -- see my "1980 14' Lowe Superior V Restore/Repurpose" thread in linked in my signature).

Symptoms: starts easily cold, and initially idles OK. Then after running for a while and shutting down for an hour or so it becomes very cantankerous, difficult to start, and really does not want to idle without some choke. That makes it really difficult to get into gear at reasonably low rpm without stalling -- I basically have to pop in and out of forward gear and fiddle with the choke until the boat gets some forward momentum. This problem presented during a duck hunt about a month ago, but it was only a very short run so it wasn't a big deal. I thought the problem was a loose low-speed idle knob (which tended to drift out of the proper position and toward "lean") -- fixed that. Motor started easily at home, and would idle fine in a barrel of water for extended periods, lulling me into that dreaded false sense of security.

The misbehavior came back and presented a huge problem while out duck hunting with a couple friends yesterday on a big lake in 15-20 kt winds with temperatures dropping below freezing. Again, the boat performed fine while motoring in and idling around while putting out decoys. About 2 hrs later, while going out to retrieve a drifting decoy, the motor stalled when I throttled back and I had a real hard time getting it started again, the 14-ft semi V wallowing about in 3 ft swells (which, fortunately, it handled with aplomb). I shuttled one person back to the dock and the motor stalled when throttling down for the no-wake zone -- took many pulls to get started (exacerbated because the recoil spring decided not to take up more than about 8 inches of the pull cord). Went back to get the other hunter and decoys, and used a trolling motor to maneuver around. Fired up the motor the head back in, but we wanted to retrieve a drifting decoy out of open water. You guessed it -- stalled when I throttled down, and really couldn't get it back started. Pullcord broke, and went to the old school cord wound around the flywheel, still couldn't get it going. Used trolling motor to cross open water (mostly cross wind) toward the lee and ultimately to the cove with the boat ramp. About 100 yards from the dock (after running the trolling motor on high for probably 20 minutes straight, covering about 1/2 mile), trolling motor quits, 10 ga wires smoking (not fused -- the kind you clamp direct to the battery terminals). Disconnected the wires quickly, and dropped them in the lake to cool.

My companion went to plan C and started paddling, which basically just kept us in place because the wind had now shifted to being more against us, while I tried to get the motor started. Finally got started and successfully in gear, motored to the ramp. And, no, we didn't get any ducks.

Practically everything that could have gone wrong did go wrong, except that (A) nobody went in the drink and (B) the boat never took on water, (C) the wiring did not actually catch fire, (D) the motor did ultimately work, and (E) we did ultimately make it to the ramp.

Needless to say I NEVER want a repeat of this experience. Like I stated at the top, this probably needs a complete carb tear down (I replaced all the easy stuff in the fall, but never popped the core plugs & cleaned out those passages manually), but if any of you have more specific suggestions, that would be great.

Here are some things I learned:
A) always have starting fluid on hand. I know that it is frowned upon here due to lack of lubrication (and the problem should be fixed at its source rather than relying on a can), but in a hairy situation I want that motor to START.

B) 8 ga or even 6 ga wire on the trolling motor, with fuse or circuit breaker.

C) NEVER trust performance in a barrel; if you think you've fixed a problem and anticipate going out in difficult conditions, do a sea trial under better conditions first.

Thanks for putting up with this rant.

E

 

[mekkamaz]

Re: Evinrude 1976 9.9/15 - multiple failures, but could have been a lot worse

Did you check the filter screen on the fuel pump? Sounds like when first start, you prime it well, fill the carbs, and starts fine, fuel pump maybe does not giving enough fuel and eventually dries the bowls. Then when you try start again maybe there?s no fuel. I?ll go for a fuel pump rebuild and Also a priming bulb check/change will be in order. Keep us posted. hope this helps somehow...Also check for the fuel connectors o-rings, maybe you have an air leak somewhere.. are they dry or dripping?..

 

[jmendoza]

Re: Evinrude 1976 9.9/15 - multiple failures, but could have been a lot worse

This sounds a bit framilliar, I had similar symptoms with my 1975 9.9. It turns out I had no thermostat in the engine because the previous owner had replaced the head due to corrosion(he never flushed it, used in salt water) This happened after the engine got hot and seized. He decided in order to avoid that happening again to not put in a thermostat. I found the problem and bought a thermostat and seal, but the head was corroded in the seal area and allowed the cooling water to circulate uncontrolled, resulting in an over cooled engine. It would run in a tank OK, but on the lake, in cold weather, it would die whenever I throttled back, and then require a choke to start. If I was not careful to keep it running fast, it would foul plugs too. Like you, I eventually broke the pull rope due to repeated hard pulling. I should have replaced the head, but instead we made a piece of aluminum from some tubing and pressed it into the head in the thermostat well to form a new sealing surface for the rubber seal to bear against, and this solved the problem once and for all. I initially found the problem by putting my hand on the block and noticed it barely got warm; it should get hot enough to be uncomfortable to touch for more than about 10 seconds. My 9.9 also has 15 carb I got for it, which effects a noticable power increase. The reason I did this was because the engine was way down on power at Big Bear Lake (7000 ft.). I tried a 9.25 x 8 prop, but it only helped slightly, adding the bigger carb made it so I could then plane my 12 foot Western with 3 people. Basically, it has the same power at 7000 feet as it did at sea level with the stock carb and prop.

 

[Dabbler_E]

Re: Evinrude 1976 9.9/15 - multiple failures, but could have been a lot worse

Thanks guys -- good ideas. Right now I'm waiting for things to thaw out before I test out fuel pressure and operating temp.

 

[Dabbler_E]

Re: Evinrude 1976 9.9/15 - multiple failures, but could have been a lot worse

Jmendoza, looks like you get the ribbon. Compression OK (97,102), good spark in both cylinders, good fuel pressure from pump (6-7 psi), but motor never gets more than slightly warm, even after revving moderately for 10 minutes.

 

[kbait]

Re: Evinrude 1976 9.9/15 - multiple failures, but could have been a lot worse

Get new plugs gapped to .030" and do a de-carb. If you're getting 1/4" bright blue spark on the tester, you're likely good to go. Those 9.9/15 points motors never had the strongest spark, and running 'em way cool will foul plugs.

 

[jmendoza]

Re: Evinrude 1976 9.9/15 - multiple failures, but could have been a lot worse

If the engine is over cooling, you are probably missing the thermostat, or it's seal is leaking. 1974-6 has a seven bolt thermostat cover, later years have 8 bolt covers. Take off your cover and verify you have the thermostat and seal. If not, then carefully inspect the area where the seal goes, especially if this is a salt water engine because this area will corrode out and not seal if it has been run with no seal and thermostat. The corrosion then creates pitting and the seal will allow water past and the engine will over cool. Another possibility is a piece of a degraded inpleller blade could be lodged in the thermostsat and keeping it open, but this is rare. More than likely, you will probably need to replace the head, and thermostat if it's a saltwater engine that has been run without the T-Stat. If the engine is fresh water, and has a good sealing area in the head where the thermostat seal goes, it can probably be used as is. The later 8 bolt head and thermostat covers have revised circulation for more consistant and even temperature, to reduce plug fouling and improved low speed running/trolling performance.

 

[Dabbler_E]

Re: Evinrude 1976 9.9/15 - multiple failures, but could have been a lot worse

Thermostat was busted but the seal area was OK (once some gunk was cleaned out). New thermostat, seal & gasket, and we're back in business. It was very gratifying just to hear the motor start to sound happier and happier as it got up to operating temp. I love fixes <$25. Thanks jmendoza & all!

 

[AlTn]

Re: Evinrude 1976 9.9/15 - multiple failures, but could have been a lot worse

a good decarbing would help things as well

 

[cyclops2]

Re: Evinrude 1976 9.9/15 - multiple failures, but could have been a lot worse

Be carefull about the thermostats.

My 9.9 Even has a TINY pin about .03 to .060" in diameter X about 1/4" long . Lose that & you are in trouble. I changed the pin length to get the water temperature right on the money. BINGO No more carboned up plugs. Easy starts. Tank running also looked great.
Why not. the exhaust was rapidly heating up the water.


If new plugs returns a great starting & running engine. Go for the thermostat............Or a intermittant ignition control module.

 

[cyclops2]

Re: Evinrude 1976 9.9/15 - multiple failures, but could have been a lot worse

I remember a LONG posting in the web by a guy who seemed to know why a 15 carb was not always a cure all for a 9.9 HP. See if I can dig it up again.

 

[cyclops2]

Re: Evinrude 1976 9.9/15 - multiple failures, but could have been a lot worse

Found it.

Web search Maintaining Johnson-Evinrude 9.9 part 1

 

[Dabbler_E]

Re: Evinrude 1976 9.9/15 - multiple failures, but could have been a lot worse

Cyclops2: Yes, I've consulted that "Maintaining" resource quite a bit. For my year ('76), it really is just a difference in carbs.

I'm not really sure what you're trying to say in your first post, though. I have already replaced the thermostat, and this model has no ignition control module (has points & coils).

 

[cyclops2]

Re: Evinrude 1976 9.9/15 - multiple failures, but could have been a lot worse

My newer 9.9 has full electronic ignition.
Intermittant on the water. NEVER NEVER at the best mechanics test tank for 1.5 years. Finally acted up for him. I replaced at least 8 sets of plugs & a thermostat. He charged me $ 38 dollars for P & L.
I am sooo happy for the last 2 years.

I now have a simple plan for any engine problems now. I run 2 loads of Sea Foam thru ANYTHING that acts up. Not back to great ?

It goes to the shop. Sea Foam has solved any roughness so far.

That tiny pin sits on top of the thermostat. I HEARD it strike the Aluminum hull.

Rich