Rev up on start

[NiVani 1]

We have twin 150hp 2010 models insttalled on our 7.5m.

Just recently, when starting one engine revs up to 1200rpm then drops rev and most time dies
what could cause this?

[boats.net]

Need to check for sensor fault codes, have it checked with computer diagnostic.

[RussArran]

How many hours have your engines done?

[NiVani 1]

#RussArran- 300-400hr only, and we run them on the water once a month when not busy.

#boat.net - will get dealer to come down and put his computer on to it.

Cheers

[redlowrey]

#RussArran- 300-400hr only, and we run them on the water once a month when not busy.

#boat.net - will get dealer to come down and put his computer on to it.

Cheers

What doe's it do the the next time the key is turned to the start position doe's it run normal, or rev up and stall again.

[Harper]

Read this whole thread... http://www.suzukioutboardforum.com/s...odd-start.html ...you might find an answer.

[redlowrey]

Read this whole thread... http://www.suzukioutboardforum.com/s...odd-start.html ...you might find an answer.

Yes and I will tell you why. Have you ever lifted the bonnet of a small car with a 1.5 to 2.5 litre engine in it and seen how small the battery is, and you think to your self why is the battery in my four stroke huge, its called voltage drop, when they make ecu's for automotive cars they have built in software to compensate for voltage drop, e.g. for fuel injection pulse width ignition dwell and so on so the engine will still start and function with a cranking voltage as low as 7 volts. Because the engines are small say like my df140, having a large capacity battery, and because the cranking current is not high and the voltage drop is low and they can get away without the added software. So when you get weird glitches on start up check the voltage drop on crank.

[cprice1]

revving

Moved the white computer power wire to the battery side of the battery cut off switch and it stopped the revving on my 2008 150

[Harper]

Right on , Red. And add to that the fact that the charging system on the outboard is not as strong as the modern automotive alternator and will not fully charge those large batteries (which is why we use battery chargers to top off the batteries at the end of the day), plus the distance from the batteries from the outboard, in many cases around 10ft (3m to you Aussies) and it starts to add up to low voltages at the ECU, especially on start.

[NiVani 1]

Thanks all for the suggestions will go through them all and see if i can eliminate this issue.

i noted on the last run, they returned and shout down engine, them 15 minute later tried to start up again, the engine just cranked and cranked, once the throttle was engage in natural the engine started.

cheers
stephen

[redlowrey]

Thanks all for the suggestions will go through them all and see if i can eliminate this issue.

i noted on the last run, they returned and shout down engine, them 15 minute later tried to start up again, the engine just cranked and cranked, once the throttle was engage in natural the engine started.

cheers
stephen

Do you mean you opened the throttle a bit in neutral and it started. Do this simple test put a digital multimeter on volts and hook it up to the crank battery and get some one to crank the engine and see what the voltage drops down to on crank. I don't get any weird glitches in mine, but in saying that the places I fish are a minimum hour and a quarter driving before the engine gets turned off, so the batteries gets a good charge. Also I often leave the batteries on a trickle charge if I am not going out for a while.

[NiVani 1]

Redlowrey,

will do the voltage check when i have her out of the water tomorrow. thanks