Non-Starting BF 9.9hp Outboard help please.

[wagstar]

The engine was running sweet as you like two days ago, went to start her and it wouldn't fire up. This is what I've done so far:
BF9.9hp Honda outboard, pull start from 1996. It was working fine but chugged to a halt and won't restart. I've taken the fuel filter off and when i squeezed the fuel bulb fuel shot out of the filter, the right fuel is in the tank and clear, the tank is nearly full. Took the spark plugs off and they weren't corroded but they weren't overly wet either, considering i have been trying to start it for a couple of days, I pulled the starter string with the plugs out and no fuel was ejected from the spark plug hole, when the spark plug was placed against the the engine and the starter pulled there was no spark, but when I pulled the starter string as the spark plug was being put against the engine there was a bright blue spark arcing from the bottom of the spark plug to the engine. There is a 15a Fuse on the motor but that is intact. the engine turns over when the starter string is pulled but it doesn't sound like it wants to even try to start.

If anyone can offer some advice as what to try next, i would really appreciate it. Thank you.

 

[jgmo]

Hi,

Sorry you're having difficulties.

Your account of checking for spark is a little confusing to me but let me see if I have it straight:

You say that when you hold the spark plug's grounding "strap" (little "L" shaped metal tab on the end) against the block and pull the starter....there is NO spark. BUT...when you pulled the starter JUST as the spark plug was being held in close proximity to the block....a spark jumped from the "strap" portion of the plug to the block. Is that correct?

Well....even if it ISN'T an accurate recount of what you were trying to say...it does show that the ignition is TRYING to fire. And, if that IS an accurate account of what is happening....it could be that the plug is INTERNALLY GROUNDED and needs to be replaced.

The ignition system on these engines fires in BOTH cylinders at the same time....EVERY TIME. So, if one side is grounded for some reason....NEITHER cylinder will fire and the engine ignition will seem to be "dead". You proved that it isn't dead but that there may be a fault. Grounding the ignition is EXACTLY how you go about shutting the engine down when it's running. So a grounded plug could bring everything to a halt.

The FIRST thing I would suggest in this case is to disconnect the STOP/KILL switch to eliminate the possibility that it is somehow grounding out the ignition. CAUTION: if the engine starts with the switch disconnected...you have no QUICK way to stop it with the switch disconnected. That's why I use a set of "jumper" wires when I do this to maintain total control. Also...do your testing with the water pump intake submerged so that you don't do any "dry starts" and the engine doesn't overheat while you are trying to get it stopped.

If the engine still will not fire with the kill switch disconnected...replace the plugs. Use the NGK plugs ONLY. DR5HS I believe.

Although...you could just replace them right up front and skip the first step. If it fires with new plugs...then you're back in business. If not...go back to step one....the kill switch.

I wouldn't worry a great deal about not seeing fuel coming from the cylinders when you pull it over with the plugs removed. These engines "sip" fuel...not drink it. So I wouldn't expect a great deal of "wetness" from a few strokes of the pull cord. BUT...if you spend a great deal of time pulling the engine over with a no start and the engine IS getting fuel...there's a possibility that the fuel can eventually "wash" down the cylinder walls and enter the crankcase. Thus, contaminating the engine oil. So be careful of that.

A more accurate method for checking spark is to use one of the jumper wires I mentioned. A jumper is simply a section of wire with an "alligator clip" at each end. Remove the plug...attach one of the wire clips to the ground strap of the plug...ensuring that the plug and the wire clip are INSULATED from being grounded. Then, attach the other clip to a RELIABLE engine grounding point and pull the starter cord while observing. This "mimics", electrically, what actually takes place with the plug installed in the engine. If you do this in the daylight, it may be difficult to see the spark. Honda spark can be considered "good" even if it's hard to see in the daytime. A darkened garage or a blanket over your head and the engine while a helper pulls the cord makes seeing the spark much easier.

Try the new plugs and ignition switch tip...if necessary...and get back with results. If it turns out that the ignition IS firing...there are other things that could keep the engine from starting and not enough fuel COULD be one of them. But before going down that road let's eliminate one thing at a time.

Good luck.

 

[jgmo]

One other thing about spark. hondadude recently posted an EXCELLENT description of just how your ignition system works. It can be read in a thread titled:

She's on, She's off, intermittent fault.

Posted on 9-25-2015 and updated yesterday by spudgun60

If you would like to know more about the ignition on the 9.9...please give it a read.