Okay, I'm desperate. Backfiring when starting then it tries to run backward

[mikeroth]

Late 70's merc 90hp w/ elec ignition hard starting, backfiring and backwards run then die's . Crank and distrubitor keys checked, new timing belt, Dist Cap, Starter and plugs,Wires check out ok, float level ok good fuel pressure. Ran fine one day the next day this was our problem any idea's??? This motor was installed into a different boat and the Tach is also not working. Has anyone had problems with elec remote controls associated with this motor and could they cause the problem? <br />--------------------------------------------------------------------------------

 

[JB]

Re: Okay, I'm desperate. Backfiring when starting then it tries to run backward

Ahoy, Mike.<br /><br />Every now and then someone mistakes our Fora for a chat room. Check this out.<br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=17;t=009035 <br /><br />Your engine is firing way too advanced. The linkage that advances the ignition as the throttle is opened may be stuck at full advance or there may be a missing or broken spring that is supposed to retard it as throttle is reduced.<br /><br />Good luck.

 

[what200]

Re: Okay, I'm desperate. Backfiring when starting then it tries to run backward

Is this a dist motor?<br /><br />Check your firing order.

 

[mikeroth]

Re: Okay, I'm desperate. Backfiring when starting then it tries to run backward

Nope, but thanks JB. <br />Any other ideas?<br />This wasn't the problem.

 

[Kenny Bush]

Re: Okay, I'm desperate. Backfiring when starting then it tries to run backward

Is the starter spinning the motor the correct direction? Is firing order correct? Did anyone mess with the power pack wires? Check it out and Post results.

 

[what200]

Re: Okay, I'm desperate. Backfiring when starting then it tries to run backward

I'm not aware of any fishin motor inline ever being built counter rotation so the starter wouldn't work even if wired in reverse.<br /><br />Since it is distributor motor and you've checked firing order it is possible the dist drive belt has loosend and jumped a tooth or two or something happened inside of dist.<br />To roughly (quickly) check timing: Pull all the plugs and ground all to block except #1. Looks in #1 cylinder hole and turn flywheel until you see piston at top of cylinder. Look for the sticker on the flywheel-- it should be close to TDC mark. Put a screwdriver (or something metal) in the plug boot and hold 1/4" off block. Turn flywheel once back around and stop when you see it spark. It should be close to that TDC mark on flywheel. If not then order is wrong or timing is out of whack. If that checks- find Tdc with the other cylinders and repeat. A quick and dirty way to get TDC on the other cylinders is to stick something like a long bolt about a half inch in the hole and rotate flywheel until it hits, mark the flywheel at timing pointer then turn the other way until it hits, mark and TDC is half way between two marks. <br /><br />This only works on dist motors since the spark is batt fired (Key must be on too). If you want to check the timing more accurately then a dial gauge is very helpful.<br /><br />The tach is driven by the stator and the rectifier. A bad rectifer would still let the motor run. I don't know if it is possible a bad stator could done what you described. But I'd check the timing first and then the stator.