1993 15 hp Johnson Stalling

[93Johnson]

A month ago I experienced stalling at low idle. I took it to a dealer/mechanic and at $140 per hour he adjusted the idle. It worked ok for a while and then I experienced it again as well as a loss of power. They suggested that it could be the head gasket and for another $325 they could change the head gasket . I subsequently changed the head gasket, oil seals and installed a new gas pump. Took it out on the water today. Started right way and went some distance before full throttle. When I lowered to low(est) idle it stalled. Restarted same throttle up and down and it stalled - repeatedly. The mechanic said the carburetor looked fine so now what? I did put some sea foam in (just in case) but that made no difference. What do I do next? I’m not a mechanic. Change gas line? Gas tank? Get a new motor?

Any suggestions? Please?

 

[racerone]

I would steer clear of a shop that charges $325 to change a head gasket !!----Post your compression numbers.----Perhaps test run with another tank and hose.----Water pump impeller changed recently or never ?-----Your location ?

 

[93Johnson]

I would steer clear of a shop that charges $325 to change a head gasket !!----Post your compression numbers.----Perhaps test run with another tank and hose.----Water pump impeller changed recently or never ?-----Your location ?

Compression 58 - 58. Impeller is fine. Great flow. Changed a few years ago.

 

[racerone]

Those compression numbers are awful.-------You have a bad gauge, bad head gasket or a motor that needs overhaul.----Test with another gauge.

 

[Crosbyman]

btw... I would ask that mechanic what his compression #s were after the $325 head gasket job , seal, gas pump job???? surely he retested compression #s to check out his work ????

you indicated not being a mechanic but just out of interest you may what to read the attached topics.
Johnson_carb (leeroysramblings.com)

the site called Leroy's will give you all sorts of info on the series of engines ...see link
OMC 9.9 - 15hp (leeroysramblings.com)
I know some sections are not applicable to your problem so just skip over as you see fit

Johnson/Evinrude 9.9 / 15 hp General Info & Normal Repairs 1974 - 1992

Johnson/Evinrude 9.9 / 15 hp Powerhead / Midsection Repairs

Johnson/Evinrude 9.9 / 15 hp Carburetor / Fuel Pump Repairs

Johnson/Evinrude 9.9 / 15 hp Lower Unit / Water Pump 1974 - 2005

Johnson/Evinrude 9.9 / 15 hp Water Circulation Problems

Johnson/Evinrude 9.9 / 15 hp Troubleshooting

Johnson/Evinrude 9.9 / 15 hp Converting Shaft Lengths 1974 - 2005

Johnson/Evinrude 9.9 / 15 hp Converting to Electric Start 1974 - 1992

Johnson/Evinrude 9.9 / 15 hp General Info & Normal Repairs 1993 - 2005

Johnson/Evinrude 9.9 / 15 hp Converting to Electric Start 1993 - 2005

 

[Sea Rider]

Gee, the dealer/mechanic is a highway robber to pretend collect $ 325 for a simple head gasket change. Who finally changed the gasket, the dealer or yourself ? A motor whith such low compression if real will be difficult to start but not die once started.

Most times the mechanical part it's blamed for, but if in good working cond it's an electrical related issue. Any component heats up and shuts the motor down, will restart once cold to miss again in a row specially if being such a 27 year oldie. If all the mechanical parts are in excellent working order, that motor needs a full electrical troubleshooting....

Happy Boating​

 

[racerone]

He seems to indicate he changed the head gasket himself.----I should move to where folks are willing to pay $140 / hr.----Where is this neighborhood ???

 

[Crosbyman]

Sea rider... 27 year oldie ...? that is not old if it was taken care of...

all my 50-60 year oldies picked up a for 50-100$ (cheaper than that head gasket job) work fine, purr all day long my favorit being my $50 9.5hp 9622a (mid 60s )

 

[Crosbyman]

original post is confusing where OP states ...I am not a mechanic

yet ... I subsequently changed the head gasket, oil seals and installed a new gas pump.

 

[93Johnson]

btw... I would ask that mechanic what his compression #s were after the $325 head gasket job , seal, gas pump job???? surely he retested compression #s to check out his work ????

you indicated not being a mechanic but just out of interest you may what to read the attached topics.
Johnson_carb (leeroysramblings.com)

the site called Leroy's will give you all sorts of info on the series of engines ...see link
OMC 9.9 - 15hp (leeroysramblings.com)
I know some sections are not applicable to your problem so just skip over as you see fit

Johnson/Evinrude 9.9 / 15 hp General Info & Normal Repairs 1974 - 1992

Johnson/Evinrude 9.9 / 15 hp Powerhead / Midsection Repairs

Johnson/Evinrude 9.9 / 15 hp Carburetor / Fuel Pump Repairs

Johnson/Evinrude 9.9 / 15 hp Lower Unit / Water Pump 1974 - 2005

Johnson/Evinrude 9.9 / 15 hp Water Circulation Problems

Johnson/Evinrude 9.9 / 15 hp Troubleshooting

Johnson/Evinrude 9.9 / 15 hp Converting Shaft Lengths 1974 - 2005

Johnson/Evinrude 9.9 / 15 hp Converting to Electric Start 1974 - 1992

Johnson/Evinrude 9.9 / 15 hp General Info & Normal Repairs 1993 - 2005

Johnson/Evinrude 9.9 / 15 hp Converting to Electric Start 1993 - 2005

Thanks for the info.
I did buy an online manual (it’s Greek to me) and I have read Leroy’s Ramblings (What a guy).
I should also say that when I run the motor on my driveway (with hose and rabbit ears) it runs fine. the problem is in the water. I think I need to increase the idle and figure out the gas flow, ie. carb, tank and fuel line.

 

[racerone]

Well on a hose there is no load and no back pressure.----So they all sound just fine to the untrained ear.-----Many motors have been sold running on a hose.----They " bark and roar " and sound powerful.

 

[93Johnson]

Not a mechanic but, youtube is an excellent resource and this motor is very simple to do those 3 jobs. In fact, I was shocked that I could do the head gasket in less time than it took me to drive to the dealership ie. under an hour.
At a shop rate of $140 an hour (Vancouver) it becomes quite prohibitive to have the shop look for the problem and that’s why I’m trying to do it myself.
fascinating that SeaRider suggested electrical. When I was testing the motor on the river yesterday, for the first time ever, my electric start kept shorting(?) I think. By that I mean, it wouldn’t shut off and I finally had to disconnect from the battery.

 

[racerone]

??------The ignition / spark making system does NOT use 12 volts from the battery.----The 12 volts from the battery only runs the starter motor.-----And disconnecting a running motor from the battery can lead to expensive damage to the battery charging system.

 

[Crosbyman]

adjusting the idle could be as simple as adjusting the idle screw on the carb (fat slotted screw top left side of the carb)
could be crud in the gas water etc... clogging the LS needle setting

(unscrew it ... ... blow carb cleaner in the LS channel
blow air reset the idle screw in the approx same position by gently closing it shut and then back it out about 1 turn ..try to start the motor after pumping the fuel line pump hard

another issue as describded in Leroy's article is the tiller setting which can vary a bit. how does the engine run if you increase the speed just a bit on the tiller ?? maybe LOW is to low ..see Leroy's comment on this

 

[93Johnson]

Hmmmm. I think what you suggest is my next step. your description of the screw is good. I looked on the schematic for ’idle screw’ and is there another name for it or a number? From the schematic?

Thanks

 

[93Johnson]

Found the screw. Good description. Now I have to go buy some carb cleaner.
FYI. I’ve had the boat for about 12 years and it’s always had a problem with low idle. The problem is much worse now but I have never been able to troll without it cutting out.

 

[racerone]

Item 15 is the low speed / idle mixture screw.

 

[93Johnson]

Perfect. Thanks.

 

[Crosbyman]

that $140/hr mechanic should have done all this but it is to late because he won't touch it after you have done some work on it.... anyhow...to late

I am not to up on this model of carb mine are all older style.

sucking fuel comes from the upstrokes on cylinders so either fuel is not flowing properly in the carb (you can try pumping the fuel bulb and if ok something is wrong in the natural fuel flow such as bad/restricted hose, air leak, bad fuel pump etc...) ...you do open the tank vent ?

or air can't be sucked in forcefully enough to drag the fuel inside the crankcase . Make certain the airbox is not causing restrictions (nice homes for bugs)

drop in on the utubes for your motor maybe someone had the same issue.

patience brings joy !

 

[werewolf30]

I have a 91 15 johnson electric/rope start i traded for the kid had it all apart and i used gm top engine cleaner in the cyllinders and to clean the head, soaked it good and flat sanded the head put a new gasket on it ,, oiled the cylinders with two stroke oil put head on and had 120lbs compression, kit ed the carb,cleaned the three holes on top the carb for idle and fuel pull thru and checked timing and motor wants to climb outta the barrel clamped down in gear,, so you might want to try cleaning it with the gm top engine cleaner and then see what compression you have,, ive run it about a year starts great cold and hot and thinks its a 25 haha , those three little holes on top the carb body are critical to be clean. and have the float set even with the gasket.