Hello folk's, I am hoping to see if anyone can help me confirm my suspicions that my CDI is failing. I have put up with the problem long enough to be able to reproduce it every time I am running it.
Here is what I have been able to observe:
At a given throttle position (3600 rpm), after about 30 seconds I will start to lose rpm's , at first it will drop 100-200 rpm's and then over the next 30 seconds if I do nothing it will eventually drop all the way down to 1200 rpm and then suddenly quit. It will always start right back up, accelerate fine and then repeat the problem. If I keep the rpm below 3400-3500 it will run perfect all day long.
When it is starting to drop from 3600 rpm if I slowly pull back on the throttle it will suddenly recover and providing I don't give it any more throttle it will run at that rpm (3400-3500), all day long.
I believe it to be related to a throttle position issue because if I load the boat up with passengers it will behave the same, but at a lower rpm, approx 3200 rpm.
While trying to diagnose the problem last season the entire fuel system was cleaned and new carb kits and a fuel pump were replaced. Given how the engine so suddenly recovers by reducing the throttle it really seems like the ignition is cutting back in. I have hooked up a timing light up to all three cylinders and at no time do I lose spark to any of the cylinders when it is losing rpm.
Have given the wiring a good look over for wire rub through's and have disconnected oil and temp sensors to eliminate them.
Has anyone seen this, or have any suggestions? The CDI is really expensive and I would sure like to have some confidence it is the problem.
Here is what I have been able to observe:
At a given throttle position (3600 rpm), after about 30 seconds I will start to lose rpm's , at first it will drop 100-200 rpm's and then over the next 30 seconds if I do nothing it will eventually drop all the way down to 1200 rpm and then suddenly quit. It will always start right back up, accelerate fine and then repeat the problem. If I keep the rpm below 3400-3500 it will run perfect all day long.
When it is starting to drop from 3600 rpm if I slowly pull back on the throttle it will suddenly recover and providing I don't give it any more throttle it will run at that rpm (3400-3500), all day long.
I believe it to be related to a throttle position issue because if I load the boat up with passengers it will behave the same, but at a lower rpm, approx 3200 rpm.
While trying to diagnose the problem last season the entire fuel system was cleaned and new carb kits and a fuel pump were replaced. Given how the engine so suddenly recovers by reducing the throttle it really seems like the ignition is cutting back in. I have hooked up a timing light up to all three cylinders and at no time do I lose spark to any of the cylinders when it is losing rpm.
Have given the wiring a good look over for wire rub through's and have disconnected oil and temp sensors to eliminate them.
Has anyone seen this, or have any suggestions? The CDI is really expensive and I would sure like to have some confidence it is the problem.