!!!HELP!!!1995 90hp yamaha outboard

[pier 1 marina]

Problem: Motor fires on cylinders 1&3 for 3 seconds and then stops firing. #2 never fires. The motor will start and then die after 3 seconds. Hit the key and motor fires instantly and runs for 3 seconds then dies. Every so often the motor will stay running for about 5 to 10 seconds then dies again.

Actions taken: Different control box and harness, ymis computer, pulser coil, charge coil and crank position sensor. All parts listed have been tested and show to be within spec according to manual.

Any suggestions as to what i should try next would be greatly appreciated!!

Thanks in advance

Engine model #90tlrt

[robert graham]

Same motor as mine. Maybe check and establish that some of the simpler, more obvious mechanical parts are working correctly, like the fuel delivery system, fuel pump, filters, carb floats, drain carbs, checked for air in-leakage at fittings, O-Rings, gaskets, primer bulb check valves. I believe about 85% of problems with these motors is fuel delivery related, and not electrical. Good Luck!

[99yam40]

If you have tested the peak voltages of the inputs to the CDI then I hope you also tested the out puts to make sure all meet manual specs.

Motor needs good compression and spark along with spark at the correct time(timing). and then it is the ratio of fuel to air to get the proper firing of the cylinders.

always test what you can and then work on the things you find bad or if none are found work on the things you can not test to see what is wrong.

Fuel supply is easy to test with a fuel pressure/vacuum gauge, and spraying a fuel oil mix into carb throats will show if they are running lean on fuel. Not sure how to tell if they are flooding except seeing fuel running out of carbs while running or pumping primer

[throrope]

2x on robert graham

We replaced all upstream of the outboard and cleared the carbs. Seems we didn't get all, but after last weekend idle seriously degraded Fires on all when opened up, but sounds like one or more miss at idle. I'm thinking the fuel lines within the cowling and downstream of the filter are an issue and clogged what I just cleared.

Oh well, back to the beginning.

[hewesbayfisher90hp]

Same issue

Sounds like we have the same issue, just posted up today - so will keep you informed of what I find out.

[robert graham]

Maybe check plugs for indications of rich fuel-fouled condition caused by bad/ruptured fuel pump diaphragm?

[Tucker]

Yep, some of us have been bit the same way. Clean the carbs just to pump fouled fuel into them. After cleaning a second time; I removed hose at motor side filter and hand-pump filled a 2-quart Gatorade bottle. That way you can see if you got bad fuel.

[hewesbayfisher90hp]

Not a fuel issue

This is not a fuel issue - have you tested the voltages or only used resistence readings?

[ausnoelm]

seems to me you are just tossing parts at it in the hope you will fluke a fix (and in the end you might) what you need to do is to get a genuine manual (if you don't have one) and systematicly trouble shoot the motor, "fixing" everything and anything is a sure fire way to empty your wallet and possibly introduce a few more faults along the way, your motor is quite simple and does not require a lot of sofisticated test equipment.

[Holoubek]

!!!HELP!!!1995 90hp yamaha outboard

What was the problem?

[YammyMan]

I would look for insulation worn from wires coming from underneath your flywheel all the way to your control box. Sounds like your motor is shorting the kill switch or coils. I would say check the integrity of your wiring.