TOPIC: T-Bolt ignition questions

I have very limited experience with the T-Bolt ignitions

A good friend has recently purchased a Glastron powered by a very minty 150 tower. I'm not sure on the year - maybe a 76??

Anyway, the internal harness had the typical rotted insulation, so he had a mechanic in his city replace the harness. He also had the fellow overhaul the fuel pump, install fresh spark plugs, and replace the disto belt.

Over the 4th weekend I met up with him and we tried to take the boat out for a spin. The boat ran like a scared jack rabbit for about 20 minutes, but then it started to lose power and bog down horribly. The engine would start up and idle beautifully in neutral, and when in gear. Upon partial throttle (somewhere around 1,500rpm) the engine would bog down & the more throttle given, the worse pooped out. If you try to hammer the throttle, it dies instantly. Having someone squeeze the fuel bulb during this stumbling of the engine is of no help. Bumping the choke button a couple short bits makes the problem worse as well. I pulled the carb tops off, and each bowl had fuel, no floats saturated. The disto was advancing as the throttle was opened.

I am wondering if the pulse pack or coil could be at fault? Since the majority of my experience is with OMC engines - that is what I would instantly suspect with one of those. However his mechanic told him the T-Bolt either works or doesn't with no in between or partial functionality. All or nothing. I can't help but think this is complete B.S. but since I'm not an authority on these - I would greatly appreciate the opinions of those that are the experts on these..

Any help appreciated & I will forward your responses to my Buddy with the Merc in question.

Thanks!

One thing not-ignition-related that you might check is the fuel pump diaphragms. A ruptured diaphragm might be flooding out a cylinder. Just a thought, since choking does no good; sometimes on these, too-much fuel is harder to diagnose than not-enough! Of course, an easy way to check that issue when you're running is, when it starts acting up, unplug the fuel line and see if it cleans itself out before it runs out of gas.

On the ign, my buddy the Doc has seen a trigger act up for quite a while before it died; pretty unusual, as your Merc Guru said they usually work or not. But it does happen.

You may have to check system voltages with a DVA to see what's going on.

The easiest way to bypass the distributor trigger circuit and do a functional test on the coil and switchbox is to disconnect all (3) distributor wires; jumper together the distributor-side brown and white terminals; then every time you ground the black terminal with the key "ON", it'll spark.

You can do a "stress test" and spark for a few minutes to see if anything changes.

It's also a good way to check firing voltages without having to crank over the motor or run it on a flusher.

And just for the record, switchbox and coil failures are much less compared to problems with the trigger.

Here's an excellent online troubleshooting info from CDI Electronics, if you haven't seen it already:

issuu.com/cdielectronics/docs/troubleshootingguide?mode=embed&layout=http%3A%2F%2Fskin.issuu.com%2Fv%2Fcolor%2Flayout.xml&backgroundColor=000000&showFlipBtn=true

Page 66 starts with breakerless CDI troubleshooting.

HTH & G'luck!........ed

If your buddy goes out on the lake to try the test that Ed mentioned (unplug the gas) I would also recommend to try uncapping the gas tank. Listen for a hiss. It may not be a vent issue, but as long as you're out testing, it'll only take 15 seconds.

Will

I have had a weak coil cause similar issues. Switch box/ trigger in my experience usually is a non running motor.
There were two style coils early 1500's had a large one mounted over the fuel connector area, that's the style I've seen your problems with. The later smaller ones mounted to the block under the distributor not so much. Also bad wiring job can make for poor low voltage side connections unable to carry the needed current yo run the TBolt system so check all of this, all wires leading to BOTH sides of switch box should be inspected twisted etc..
Randy

Thank you everyone for the suggestions. Joe Pool kindly called me about this issue and shared a lot of information about the engine and possible things to check. Since i don't have the time to mess around with the motor, my friend is taking it back to the place that did the previous work. We both agreed that the mechanic needs to understand that this isn't some old beater that he wants "Band-Aided" back together - he wants it COMPLETELY shopped out. That means all new alcohol resistant hoses ans fuel system parts, and anything else that could be deteriorated by age. As suggested above, Joe Pool is inclined to think that the issue is fuel related. He is probably right. But he did mention the same thing as Randy about the early coils - the large orange one mounted to the lower pan. This motor has one of those - and if the issue isn't junk in the fuel system, then I'm inclined to think that it's the coil. I'm pretty stubborn in my original feeling that the motor has a weak ignition problem. But some of the hoses on the system are visibly aged and cracking - so those need to be addressed first.

Thanks everyone & I'll let you know what the problem really turns out to be - when ever that finally is discovered.

Those coils are pretty bulletproof I would be very surprised if that turns out to be the issue. The thing is, do the troubleshooting by the book and only by the book, skip NOTHING and be sure to double check the readings with a DVA. Do this, and all will be revealed.