1986 Yamaha 90 HP-PLEASE help me!!

[Doogie]

I am having problems getting my 1986 Yamaha 90 HP outboard to start. When I go to start it (especially after it sits several days) I have no fire at spark plugs. I thought it was flooding at first, but had carbs cleaned and still does same thing. After cranking off and on for about 20 minutes it will finally fire off. When it doesn't start, there is no fire to plugs. Then all of a sudden it will start firing and crank right up. It runs fine after it finally starts. I know that it is getting fuel as plugs are wet with gas when this happens. I feel that it is something electrical, but can't really put my finger on anything. Please give me some ideas of things to check, as I now have a motor that I can't depend on. Very embarrasing at launch. Thanks for your help in advance!!!

 

[jim dozier]

Re: 1986 Yamaha 90 HP-PLEASE help me!!

You say there is no fire. By that do you mean the engine is not "firing" or that there is no spark. Big difference. Engines won't fire unless there is a strong spark, properly timed, and the proper fuel/air mixture in the cylinder. Pull the plugs and check for a strong (3/8 to 1/2 inch) blue spark on all cylinders (best to get a spark tester) and let us know whether we are dealing with a spark or a fuel issue.

 

[Capt Ken]

Re: 1986 Yamaha 90 HP-PLEASE help me!!

Whoa a minute. Just check to be sure its sparking. You won't get the same spark jump out of a Yamaha as you would another brand of engine. The spark will look yellow or orange but as long as you get something, the fire is good. We get several a year that bubba down the road has checked with his spark tester cranked out from checking Mercury's and OMC's and claimed they weren't firing right. But then bubba don't work on Yamaha's and he sends them down the road. Be sure your cranking speed is up to snuff. If its spinning slow, its hard to light off.

 

[jim dozier]

Re: 1986 Yamaha 90 HP-PLEASE help me!!

I'll defer to your experience Capt. What's the deal with Yamaha ignitions. I've never worked on one. My Suzuki has a capacitive discharge ignition that puts out a spark like a Mark IV phaser rifle. I thought all of the modern (post 70's) ignitions were pretty gnarly.

 

[Doogie]

Re: 1986 Yamaha 90 HP-PLEASE help me!!

jimd and Capt Ken....thanks for the replys. I originally checked it by using a nail in the plug wire and watching for spark at plug. I had none until after cranking off and on for about 10 minutes, then it started firing (I know because when it did start it lit me up !!). And when it did start firing the motor popped off like it was going to start. I took it to a buddy's about a week later who has a spark tester. # 2 cylinder was firing good, # 3 would spark every now and then, and # 1 wasn't firing at all (when I checked for spark using nail mentioned earlier, I was testing at # 1 plug only). My buddy mentioned it may be the "pulser coil". Do you all agree with this? What else can I check? Could the CDI box be bad? I don't think it's the fuel system because I'm getting fuel on plugs when it doesn't start. Like I said in my first post, when it does start, it runs good. I sure do appreciate any help anyone can give me with this problem, as I sure miss not having a motor I can depend on. Let me know if I can answer any further questions you might have that could help me diagnose this problem. Thanks again !!! Doogie

 

[Capt Ken]

Re: 1986 Yamaha 90 HP-PLEASE help me!!

Don't know why Yamaha's spark isn't as strong as other engine. Just the nature of the beast. As for Doogie, I've got a feeling that the cranking speed is slow on his engine. Be sure the battery is hot and you've got at least 9.5 volts at the starter when cranking.

 

[regsburg]

Re: 1986 Yamaha 90 HP-PLEASE help me!!

i know a bit on sparks <br />you said you were useing a nail from plug wire to spark plug.. <br />I think you should leave plug wire on a check spark at plugs;;.... you could try a neww plug ..if it sparks you know your plug wire is good ...and or the other plug was bad<br /><br /> THANKS BILL

 

[jim dozier]

Re: 1986 Yamaha 90 HP-PLEASE help me!!

I am not sure if this will work on your engine but I have read this on others. Disconnect the main electrical connection from the boat to the engine and wire a remote starter button to the solenoid and see if you get spark. If so the problem is in the boat wiring not the engine. If you don't the problem is in the ignition components on the engine.