1999 35Hp Johnson - Won't Idle After Long Layup

Hi All.

New member here from Brisbane Australia I only came across this forum because of Dangar Stu's YouTube channel. Great stuff!

I really like my J35TEL3EEM 35Hp 3-cyl 2-stroke Johnson I am the third owner but the engine does not appear to have done much work at all.

Because of a back injury, I converted it to Power Tilt. It took much longer than expected, lots of effort and $$$ but it is now finished.

The engine was not started for about 9 months or so. It starts no problem on full choke, but doesn't want to idle off the choke below 1500rpm. Not good.

I gave it fresh fuel and new spark plugs. But that didn't make any difference.

A new fuel filter couldn't hurt. Nor, I suppose, could overhaul kits in the three carburetors and two fuel pumps.

But are there any suggestions before going this far?

I have purchased a manual and will study that like a novel. But good advice appreciated.

Thanks.

Ian B

Yes ----Clean the carburetors.-----Adjust the slow speed mixture screws to the dimension in your manual.------Make sure you have spark on all 3 leads.-----Post compression values.-----Fuel pumps should be OK.------If oil tank is on there take it off and throw it away as far as you can.----Mix at 50:1 gasoline / oil ratio.

Thanks racerone. Much appreciated. I will order some overhaul kits later tonight.

I took the front covers off the fuel pumps an hour ago. The inner circular boss on the starboard side pump was broken. The port side was fine. This might be part of the problem since I think it could lead to a rich mixture and all three of the plugs look wet.

The engine doesn't have the oil mixing system fitted. I suspect it was removed by the original owner. It seems most do this. Was it unreliable? Mixing 2-stroke fuel is not hard but it means I can't use the leftover fuel in my car.

brw0513 said:

Mixing 2-stroke fuel is not hard but it means I can't use the leftover fuel in my car.

Click to expand...

I use the leftover fuel in my garden tractor, lawn mower, tiller, etc...
Non of them seem to mind the extra oil. they don't even smoke.

Well what a frustration! Marine Engine won't sell parts into Australia

Very odd seeing Dangar Stu is not far from Sydney.

Yeah, I got the same thing from Canada. Do you know anyone in the USA?
i called Marine Eng, had them send the parts to a hotel our company uses in Los Angeles, then had another employee who was there pick them up. They arrived in 2 days.
I had to contact the Conceirge at the hotel, & email him a letter giving the name of the person who would pick them up, otherwise they won’t release a package.
if you know anybody there, get it shipped to them, though it’s a bit more hassle to have to ship things twice.

Dealer in Ontario.----Free shipping on most items if order is $79+

The frustration continues.....

I have put overhaul kits through all three carbs and both fuel pumps. Blew compressed air through high speed and low speed jets and orifices in carbs. Very confident that all this went well.

Compression is in the range of 125 to 130psi across the three cylinders.

The spark at all three plugs jumps a 10mm gap.

The engine starts on full closed choke when hot or cold. But it still dies soon after and needs a real tickle when the chokes are open. The engine appears to be very rich. The plugs are wet and oily.

I'm beginning to suspect the power pack is the culprit.

Just a few questions before I start looking for a mechanic:

1. Is it possible for the power pack to partially work? I was thinking it would be either good or stuffed with no in-between. But not sure on this topic.

2. The oil system has been removed by a previous owner. The needle valves are still set at 9.5mm out on each carb. Should they be at a different setting given the oiling system has been removed?

3. Is it worth removing the flywheel to look for obvious signs of damage to the sensor assembly or encoder or something else?

4. I was very careful in re-installing the fuel pumps back in the same place they were removed from. The only internal difference I saw was in regards to the size of one of the plastic plungers. But it is it possible the pumps are installed in the wrong positions? How do I tell?

THanks.

So was it idling fine for you before the 9 month lay-up ??----Checked the thermostat ?-----Have you changed the water pump impeller .-----A new impeller is generally the first thing done with a new purchase !

racerone said:

So was it idling fine for you before the 9 month lay-up ??----Checked the thermostat ?-----Have you changed the water pump impeller .-----A new impeller is generally the first thing done with a new purchase !

Click to expand...

It had very good idling manners before the layup.

I have not checked the thermostat. Would it cause an idling issue?

The tell tale is very strong. Would it cause an idling issue?

I guess one wee step at a time.----Check the thermostat.-----Just so you know I have more than one of these 3 cylinder motors in my parts collection.-----Last one I repaired was abandoned because shop could not figure out that the new powerpack was defective !!

I don't want to give up on this engine. The previous owner used it twice in saltwater. The original owner apparently only ever used it in freshwater and this is credible given he lived so far inland. There is evidence of previous maintenance work, but I suspect the engine is very low hours. Unless something is revealed soon, then I will take the outboard back to the mechanic who worked on it last.

I suspect the idling issue is something simple. Am about to watch all of Dangar Stu's timing videos for a "light bulb" moment.

The need for two fuel pumps on the engine must be based on the OEM oil mixing i.e. one pump to draw fuel from the tank up to the power head, the other to force it through the oil mixing chamber. I have a lingering doubt about the slow speed needle valves. If the starboard side fuel pump doesn't have to work as hard to get fuel to the carbies then perhaps the needle valves should be adjusted.

But this doesn't explain why it idled well before I decided to get busy

Well----I believe you are wrong on your assumptions about the 2 pumps and the low speed needles.-------Hurry and run to a repair shop.

I won't be touching the fuel metering. That is beyond my ability and very likely to hurt the engine if run lean.

I will confirm, to the extent possible, that the timing is correct.

Then it will be off to the mechanic.

My outboard is now idling well

There were a few possible contributing factors (I'm 50% sure I had a bad electrical connection with the white/black wire from the sensor to the CDI unit and I'm also 90% sure one of the new spark plugs I purchased of FleaBay was not working properly).

But two out of the three carbs (#2 and #3) had blocked emulsion tubes. To find this, I had to remove the aluminium plug at the base of carb body below the main jet. Each blockage was in the bottom 1mm or so of the emulsion tube.

Removing this plug is the only real way to ensure the emulsion tube is clear. I had never done this before but the plug is included in the carb overhaul kit. Removal and installation is well described in the workshop manual.

Strangely though, one of these carbs still isn't working properly. The idle circuit is not passing fuel. I can tell because when the weather is just right (i.e. hot enough and humid enough conditions) the idle circuit gallery does not cool to the touch and the moisture from the atmosphere does not condense on the circuit gallery at the plastic housing on top of the carb.

I purchased three carbs from a motor that had been submerged. I picked the best one. Cleaned it very thoroughly and installed it. It works fine!

Lesson learned too - Before doing the thorough cleaning on the carbs, I paid a mobile mechanic to visit and find and fix the problem. He didn't even though he charged $242! But I watched what he was doing. Which was really only advancing the timing and playing with idle mixture screw. This gave me confidence to read the manual like a novel and follow the tune-up steps very carefully.

I am still very keen to find out why one of my original carbs is not drawing fuel through the idle circuit.

I would suggest getting some OMC Engine Tuner and follow the directions on the can when applying . It may help. If one can helps, run another through the motor.

about the original carb, believe the idle circuit is mainly in the top plate and/or in the passages in the top of the main body, a couple of very small holes plugged?, or the float being stuck(fuel in the bowl when taken apart?)