Hard to start a 9.9 4-stroke Honda

[makassiouk]

Hi again.
What happens is that the motor would take a bit too many pulls to start and when it does finally catch it, it would behave as flooded for a while (blue smoke, etc). So I guess the fuel gets there but not the spark. The plugs are from this spring, I don't really know if they can go bad this soon. I suspect that it does not get the spark to begin with, and then it appears after a few pulls - this is consistent with what i see if i take the plug out and check by pulling the starter - at first I see no spark and then it comes eventually. The carb is cleaned by a mechanic early this summer.
What I do now is that first I just begin to pull the starter, and then only after several pulls I prime the carb and engage the choke - otherwise it gets really flooded and it's a complete nightmare to start then.
I don't know if it's indicative of anything, but the oil pressure lamp does not begin to flash at once when I start trying, but only after several pulls on the starter (oil level is good).
Are these some electrical problems?

 

[cp]

Re: Hard to start a 9.9 4-stroke Honda

Hi again.
What happens is that the motor would take a bit too many pulls to start and when it does finally catch it, it would behave as flooded for a while (blue smoke, etc). So I guess the fuel gets there but not the spark. The plugs are from this spring, I don't really know if they can go bad this soon. I suspect that it does not get the spark to begin with, and then it appears after a few pulls - this is consistent with what i see if i take the plug out and check by pulling the starter - at first I see no spark and then it comes eventually. The carb is cleaned by a mechanic early this summer.
What I do now is that first I just begin to pull the starter, and then only after several pulls I prime the carb and engage the choke - otherwise it gets really flooded and it's a complete nightmare to start then.
I don't know if it's indicative of anything, but the oil pressure lamp does not begin to flash at once when I start trying, but only after several pulls on the starter (oil level is good).
Are these some electrical problems?

I'm no Honda expert so your previous post about your engine not idling well gave me little hint as to what might've been wrong, so I just read it with interest. The underlined parts above, however, cause me to see a possible explanation for all the symptoms you've posted, so let me make an educated suggestion (which takes you at your word that your carburetors and fuel system function properly - aside: blue smoke is indicative of oil being burnt).

First some rationale so you don't think I'm making too much of a wild guess:

? The electrical wiring diagram for your motor looks pretty straightforward. You have an exciter coil that generates voltage when the flywheel turns. That voltage is fed to your CDI (Capacitive Discharge Ignition) unit, which in turn powers both your ignition coil and your oil pressure light. The initial lack of spark and oil light indicates that both the light and the ignition coil are not being supplied sufficient voltage, at first. The fact that both eventually do function indicates that sufficient voltage is delivered or builds up, after a while.

? What would cause a "slow" buildup of voltage? And why would there be sufficient voltage once the motor starts, e.g. why might a higher idle rpm make the motor run better?

? Obviously, weak exciter coil output or a failing CDI unit could cause that. But, the exciter coil is simply a coil of wire that just sits there, so the likelihood of it failing, barring some mechanical damage, is very low. Likewise, the CDI unit is a solid state device with no moving parts, so is usually pretty reliable, and it does seem to fire the plugs once it receives sufficient voltage.

? There are, however, what look to be plug connections between the exciter coil and the CDI unit. A high resistance between the exciter coil and the CDI unit would drop the voltage from the exciter, and a low voltage into the CDI would cause a low output, resulting in weak or no spark and a dimly lit or unlit oil pressure light. A higher rate of voltage pulses from the exciter coil could overcome the high resistance, explaining the better performance at higher rpm.

So, my educated suggestion is that you check the connections to make sure that all are clean, bright, and tight.

When you are absolutely sure that all connections are clean, bright, and tight, then you will be into the more difficult troubleshooting, if the problem persists. The exciter coil can be tested by measuring its resistance but to detect the few shorted turns that would cause it to 'work' but at a lower output would require a resistance bridge, an instrument no weekend mechanic is likely to have. Likewise, testing the CDI is beyond the capability of most. The only real alternative is troubleshooting by substitution. If you have a friend who will loan you a known-to-be-working CDI unit, try it. If your problem goes away, you've found the cause. Ditto with an exciter coil. If no buddy with spares, then it gets co$tly.

I hope you just have high resistance (dirty/poor) connections that you can find and fix.

Good luck, let us know what you find.

 

[makassiouk]

Re: Hard to start a 9.9 4-stroke Honda

Oh, hey - what a good answer. Thanks a lot!