Power-pack Woes 1987 115hp OMC

[Frosstyx]

Howdy folks,

I started out thinking I had a prop issue and have since discovered that I am getting very weak spark on the port side cylinders on my OMC 1.6L SEA DRIVE. It's nothing but a 115hp crossflow. Here's the history of it.

I bought it used last year, went through it and ended up cooking a piston and ruining a cylinder due to a bad t-stat. Rebuilt the entire motor, all cylinders bored .064 over, forged pistons installed. All bearings were inspected and found to be good along with all internals and reeds.

I replaced everything else on the motor including coils, powerpacks, and the rectifier. I also replaced the tach afterwords.

I am not only getting around 4000rpms out of it at WOT and it's hitting right at 30mph. This boat should do 40 EASY at about 5100rpm(max of 5500). So I thought it was a prop issue, not so fast!

I went out today and decided to do a quick check on my plugs. Cylinder 1 was almost new looking with very little fouling, 2 and 4 were good and dirty from sitting on muffs idling. The other port side cylinder (3) was dirty but not nearly as much as 2 and 4.

The spark test showed that I was getting a very weak spark on cylinder 1 that would barely hop 1/4" and a little stronger hop on number 3 but not over 1/4".

What causes these powerpacks to get bad. I've read that if kill switch wires get crossed up it can back feed current into the pack. When the motor is running at 4000rpm it's charging battery fine. Is there anything else that could cause this issue of powerpacks failing?

 

[Faztbullet]

Single or dual packs?

 

[Frosstyx]

Dual. That's why I'm saying I think the port side pack is bad seeing as how the other side is getting excellent spark.

And as an FYI it's on a 18' glassmaster center console. Total dry weight of 1500lbs.

 

[Fed]

Have you checked the grounding for the Port side powerpack?
I'd think a bad ground there would send a reduced voltage to the Port coils resulting in a reduced voltage to the sparkplugs on that side.

 

[Faztbullet]

More likely a stator issue as it has dual charge coils ,one for each pack. Swap the brn/brn-yel connectors from the stator to the pack, if problem follows it a stator.

 

[emdsapmgr]

From a purely statistical standpoint, the power pack is the most likely failure component on any crossflow ignition system. Coils are probably the most reliable, along with the timer base. Stator is usually considered reliable. But, just because the power pack is statistically unreliable-that's no reason to just go out and replace it. Any of these ignition components are expensive, so some testing on your part will insure you only pay for just what is actually at fault. You are lucky, having two power packs. You can do a simple test. Swap the two power packs and see if the "no spark" condition moves to the other head. If so, likely the pack is bad. If your test concludes the pack is not the problem, you have another resource to try. Go out to the website: CDIELECTRONICS.COM. Get into their online troubleshooting guide for your year engine. There are excellent tips on how to do voltage output tests on the stator and the timer base, while cranking the engine. You'll need a special "peak reading" voltmeter for the test-may have to rent one.

 

[Frosstyx]

More likely a stator issue as it has dual charge coils ,one for each pack. Swap the brn/brn-yel connectors from the stator to the pack, if problem follows it a stator.

This! I did just this and the condition followed these 2 wires on that side of the stator. I am searching for a decent priced used one now. What would cause this to go bad?

 

[sutor623]

This! I did just this and the condition followed these 2 wires on that side of the stator. I am searching for a decent priced used one now. What would cause this to go bad?

Bad rectifier is usually what causes the stator to fail. Sometimes a motor overheat can do it. Hours of usage can also do it. Either way, if you have a new rectifier, Id just change out the stator and be done with it!!

 

[Frosstyx]

Yeah, the rectifier is brand new just put on. This stator is the original (almost 30 years old). I just ordered a used one from a fella in Florida.

I've ran the boat a few times with this issue and thought it was a throttle issue at first but have since found this issue. Will running with this issue a few times cause any other issues?

 

[emdsapmgr]

The stator coils that charge the battery through the rectifier are separate from the stator coils that provide voltage to drive the ignition. Replacing the stator because of a battery charging problem will not have any affect on your ignition side. Unless the stator's ignition coils are bad. Best to test the ignition side of the stator first before you spend the $.

 

[Frosstyx]

I don't have a charging problem. My issue is weak spark on port side. I ordered a stator we will see.

 

[dazk14]

Post back when you get the replacement stator, so others will have a future template for repairs.

 

[Frosstyx]

Will do. Wanted to make a correction. The port side cylinders are cylinders 2 and 4 that is where my problem lies. I got my cylinder layout all backwards, wanted to make sure it was corrected for anyone else's sake that may have this issue. Cylinder 4 is the cylinder that is lacking almost any spark, while 2 is very weak. I was going to edit my original post but it seems I cannot.

Still waiting on the part, ordered one from a salvage yard and they shipped me the wrong stator...he is sending a replacement.

 

[Frosstyx]

Well folks, it took a while but I ordered a new CDI stator and installed it. The used one I ordered ended up being DOA so I got a refund for that and just grabbed a new CDI for $165. I am now getting a STRONG spark across a 7/16" gap on all cylinders. I ran it for a good while on muffs and the temp alarm went off (well pressure) so I cut her off. I could still touch the heads but not for long. Didn't hurt anything but tells me everything is firing good.

Idle sounds much smoother and I will be water testing it this week. Thanks to all for all the help.

 

[rtek816]

I think you should check the cooling system before you cook another piston (from overheat). You don't need pressure from a well with a well maintained engine impeller and system to keep the engine cool. Is the pee stream running? Thermos replaced but the engine still overheats on muffs? Something smells fishy..... I like the name frosty. I'll go have one!

 

[emdsapmgr]

That engine should idle around 143-150 degrees. 20 degrees cooler when you get the boat on plane. One stat controls the temp for one head. So, get a laser temp gun and see what the cyl head temps are. You'll get an overheat warning horn around 200-212 degrees. That horn will silence when the powerhead gets back down to 175-which is still way to hot for normal operation. This is critical, and stats are cheap, so spend some time to diagnose the problem.

 

[Frosstyx]

Bringing this back up for an update. To start off with when I was running the boat on idle I didn't realize it at the time but my well filter was extremely clogged and my wife brought this to my attention the same day when her fancy washing machine indicated low water pressure the same day.

I replaced that filter and now it idles at about 1500 to 1600 rpm on the hose with no overheat buzzer. The pee stream is solid and has good pressure.


Talking about the motor. I took it out last night for the first time since everything has been replaced. The stator was the problem. The motor is pretty much brand new rebuilt from the block up with new heads, pistons(60 over), power packs, plugs, new thermostats, all gaskets and seals, and the flywheel and timer base are the only original removable parts left of the engine components.


When I took it out last night it idled rough for about 1.5 mins at the dock, smoked like crazy then it smoothed out and when I hit the throttle...HOLY CRAP!


Fellas my boat is finally ALIVE! It hit 5000 RPMS and 35mph in a matter of seconds and was on plane in less than 20 yards. I need to adjust the throttle to get about 5500 RPMS at WOT from it though.


Strong pee stream, no overheating, and smooth as butter. Best I can tell is I was running the boat on 2 cylinders for a bit there. Got lucky and didn't wash out the walls and cause another thrown set of rings. Thanks for all of the help. I now have a completely rebuilt (hull and motor)2016-1987 GlassMaster 195cc lol.

 

[sutor623]

Yea these 4 cylinder motors are funny. My boat would barely plane out running on 3 cylinders, and wouldn't plane at all running on two, which is understandable.