60 HP Johnson Tracker Running Issues

[mutiny]

Hello boating world! I have a Johnson Tracker 60 HP 2 stroke that is giving me some running issues. The Mod no is TJ60TLCEA.

The problem I am having is after the boat has ran for about 20-30 minutes it won't start back up again. I just went through all of the basics and the compression is 120 x 3 it has good spark, and the carbs were just cleaned and adjusted. This engine starts up when cold without hesitation and idles great FOREVER. If you shut off the motor then try and start it right back up, it starts instantly. However if you let it sit for a few minutes and try to start the motor it will NOT run. I check for fuel, primer bulb hard (even crack the line to make sure there isn't a vapor lock) and check spark again which is all good. The fuel in the tank is spotless and clean.

Once the engine has time to completely cool down again, the engine starts up instantly. The engine is not running hot and is pumping great water. I'm at a loss.

So far I have changed plugs, rebuilt the carbs just to make sure nothing was sticking, and done all of the basic diagnostic checks that I can think to do. Thanks in advance.

 

[flyingscott]

How did you check for spark?.

 

[oldboat1]

Is there a VRO issue?

If cool down is the key to restarting, it sounds like ignition parts might be overheating. When it sets after running, perhaps the power pack heats up from accumulated heat under the cover. You might check spark with an adjustable tester when it acts up.

 

[mutiny]

How did you check for spark?.

At first I used a timing light because it was handy. But since this doesn't test strength of spark, I used an open spark board with a little over 1/2 inch gap. Jumped no problem with a blue spark x 3

 

[mutiny]

Is there a VRO issue?

If cool down is the key to restarting, it sounds like ignition parts might be overheating. When it sets after running, perhaps the power pack heats up from accumulated heat under the cover. You might check spark with an adjustable tester when it acts up.

I thought that as well but there is no VRO pump. it has a small mounted fuel pump that runs off of the pulse of the engine.

Would a power pack issue still allow a 1/2 inch spark jump on a spark board. I've had engines before lose spark when there was a issue with the power pack once the engine gets hot and the part builds up resistance. This seems to be a bit different.

UPDATE: Issue seems to be fuel related? When I spray starting fluid in the carbs it fires up, then dies. If I mess with it for a second or two by giving it throttle it will sustain running as if it never had a problem. Possibly the push to choke? Hmm.. But it shouldn't need choked once warm and running. Thoughts?

 

[ondarvr]

It's not that uncommon, and not every motor likes the same routine for a warm restart.

​Try using the choke (primer, pushing in the key) and see what happens, if that doesn't work then squeeze the primer bulb once or twice while the key is pushed in. If either method helps then you can dial it better from there.

​

 

[oldboat1]

1/2 inch spark is great (assuming you get that even when the engine doesn't want to start).

does sound like a fuel issue, maybe the primer use or condition. Always potential for blocked carb jets -- recently went through that with a carb I swore was perfectly clean (smaller motor.)

 

[mutiny]

1/2 inch spark is great (assuming you get that even when the engine doesn't want to start).

does sound like a fuel issue, maybe the primer use or condition. Always potential for blocked carb jets -- recently went through that with a carb I swore was perfectly clean (smaller motor.)

These darn carbs went through an ultrasonic, plus got my hands on attention. There were no sign of debris even upon disassembly. I rebuilt them simply because I had them apart for inspection.

I will tinker with it a bit this morning and see what else I can drum up. I can't imagine that I let the choke solenoid slip if that isn't working.. Although, I don't think that an engine that is warm and recently running should need to be choked.

 

[mutiny]

So this morning I tested the primer valve and it works very well and as it should. Engine was cold this morning at about 70 degrees. After priming the bulb, and turning the key, this thing fired right up. Idles a little high but it sounds smooth and clean. In the lake it has all the power it needs so it isn't lacking much. Timing was also verified today after the engine warmed up. Currently I am letting the engine sit for 15 minutes to see if it will still give me a hard start after running. Since I didn't do anything different to the engine I'm assuming it will still fail.