1979 Johnson 115 won't start after warm up.

[TampaBoater]

So I took the boat out today, and started fine at the dock, while the warm up lever was about 1/4-1/2 way up. I lowered the lever after 3-4 mins of warming to iddle. Tried to engage reverse, engine cuts off. Warmed up some more, tried again, engine cuts off again. After that, it would not start anymore. Brought home and, after messing with it in the driveway, it still won't start. All I can see if a nice amount of gas coming out the carbs when choke plates close after cranking. Did I flood the carbs? It turns nice and strong but won't start. Help...!

 

[TampaBoater]

So i finally got it running again. I tried starting it tilt up and after a couple of turns it fired up. The problem now is that if i put the warm up lever all the way down ( it gets pushed down anyway if i try to shift) the motor drops down in rpms and eventually cuts off. Are my idle rmps set to low?

 

[emdsapmgr]

That's possible. The idle rpm's should be set when the boat is floating normally in the lake. When running at idle, put the engine in forward. Set the idle to between 650 and 700 rpm's. That's normal. The other possibility is that the engine is only running on 3 cyls. It needs all 4 cyls contributing when it's in the lake and in gear.

 

[TampaBoater]

That's possible. The idle rpm's should be set when the boat is floating normally in the lake. When running at idle, put the engine in forward. Set the idle to between 650 and 700 rpm's. That's normal. The other possibility is that the engine is only running on 3 cyls. It needs all 4 cyls contributing when it's in the lake and in gear.

So how can i verify that its running on all 4 and nit just 3?

 

[TampaBoater]

No Title

 

[Bosunsmate]

you can do a drop test, pull each ht plug lead off in turn and see if it makes any difference to engne rpm.
if it doent its a dead cylinder
use insulated pliers

 

[TampaBoater]

you can do a drop test, pull each ht plug lead off in turn and see if it makes any difference to engne rpm.
if it doent its a dead cylinder
use insulated pliers

You mean run the engine and then take the spark plug wires off one at a time to see if engine sounds different, and if it does not on a particular cylinder, that one is dead? I just wanna make sure I understood correctly.

 

[emdsapmgr]

That's correct. When you pull one of the spark plug wires off when running, you should see a noticeable rpm drop. That's normal an indicates that the cyl was firing. If you pull one spark plug wire off and the rpm's do not drop, then that cyl was not firing and needs troubleshooting.

 

[TampaBoater]

That's correct. When you pull one of the spark plug wires off when running, you should see a noticeable rpm drop. That's normal an indicates that the cyl was firing. If you pull one spark plug wire off and the rpm's do not drop, then that cyl was not firing and needs troubleshooting.

emdsapmgr your test was spot on. My port side bank is not firing. Only starboard side fires up. What is this indication of? Bad coils? But 2 coils going at the same time, isnt that unlikely? I think it might be a power pack.

 

[TampaBoater]

So i swithced the powerpack from port side to starboard side, and the engine won't start. Switched it back and it starts. I am thinkiing that if it was the power pack, then the port bank should have started with the starboard power pack. Right?

 

[emdsapmgr]

Yes, that engine has dual, matching power packs. The standard test is to swap them, as you just did, to see if the "no spark" problem moves to the other head. Usually it will, confirming that one of the packs is bad-and as you noted, it should start right back up and run on that other bank. You are correct, it's unusual if the swap does not permit the engine to fire and run on the other two plugs. The 4 spark plug coils are usually pretty reliable, and certainly 2 would not fail all at once. You may have something else going on. (another ignition component) Borrow an inductive timing light and see what spark plugs have fire when the packs are swapped/not swapped. It's possible you have a bad pack and maybe a bad timer base, too. Not sure just how electrically saavy you are, but this website has some excellent ignition troubleshooting info: cdielectronics.com. Some of the cranking outputs tests, (where cranking voltage of the stator and timer base are measured) are excellent condemnation voltages. (you'll need a special "peak-reading" voltmeter for those tests. All these parts are expensive, so a little troubleshooting time on your part will save you $ in the long run.

 

[TampaBoater]

Yes, that engine has dual, matching power packs. The standard test is to swap them, as you just did, to see if the "no spark" problem moves to the other head. Usually it will, confirming that one of the packs is bad-and as you noted, it should start right back up and run on that other bank. You are correct, it's unusual if the swap does not permit the engine to fire and run on the other two plugs. The 4 spark plug coils are usually pretty reliable, and certainly 2 would not fail all at once. You may have something else going on. (another ignition component) Borrow an inductive timing light and see what spark plugs have fire when the packs are swapped/not swapped. It's possible you have a bad pack and maybe a bad timer base, too. Not sure just how electrically saavy you are, but this website has some excellent ignition troubleshooting info: cdielectronics.com. Some of the cranking outputs tests, (where cranking voltage of the stator and timer base are measured) are excellent condemnation voltages. (you'll need a special "peak-reading" voltmeter for those tests. All these parts are expensive, so a little troubleshooting time on your part will save you $ in the long run.

Ok so i tried swapping the powerpack again, in case I missed something. Well this time it did start the motor up, BUT, instead of not firing the starboard side bank (thus confirming a bad powerpack), now I got no spark on the top cylinders of each bank, and it didnt sound the same as when it was just the one bank firing. Weird, right? Another thing, I bought a inline spark tester from HFT..but i think its crap, cause the motor starts but the light does not come on. I will be returning first thing tomorrow.

 

[emdsapmgr]

I've seen some odd things when the stator goes, regarding random misfires. Yours is pretty extreme. I'd be interested in whether it meets minimum output requirements.

 

[fredi]

are you still having no starts . fredi

 

[emdsapmgr]

It is possible one of the packs is bad. It's also possible that the bad pack was on the leads from a bad timer base. So, before you just start replacing these expensive parts, check the stator and timer base cranking voltage outputs. The CDI website will provide exact cranking voltage outputs, for instance the stator should put out perhaps 150 volts, the timer base, perhaps 0.4 volts. If the test does not show at least those voltages, the ignition part is condemned. Check the CDI guide for the exact outputs for your engine. A weak stator can show as random misfires on different plugs each rpm. Likely you will need a new pack, but verify the timer base and stator before you purchase it.

 

[TampaBoater]

It was the coil pack. Thanks guys.

 

[TampaBoater]

It was the coils. Thanks guys!