Mercruiser 8.1s fuel injected 2001 won't start! No spark on starboard engine

danvoyer

Cadet
Joined
May 6, 2006
Messages
10
I have a 2001 Cruisers 3470 with twin 8.1s mercruisers. I did some routine maintenance(changed impellers) and now the starboard engine will not start. It doesn't have any spark coming out of the coil packs. I've swithced all the fuses, relays, crank position sensor and camshaft sensor but it still will not start. I've checked all the wiring harnesses they all seem tight and I don't see any broken wires. I can't find this problem occuring to anyone else when I search the forums. I had a marine mechanic plug in the quicksilver computer as well as a laptop and they can't seem to find any codes that shouldn't be there and told me there wasn't anything else they could do at that time. I assume I'll have to take it to a mechanic for thourough troubleshooting but was hoping somebody had a tip on what I could have done, or if it is completely unrelated to the impeller change.
Over the past few weeks when the RPM went above 3500 rpm on the starboard engine the engine alarm went off but as soon as I slowed down it went off, again not sure if it's all related.
any help would be appreciated.

thanks!
 

wingless

Petty Officer 2nd Class
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Jul 7, 2009
Messages
195
Re: Mercruiser 8.1s fuel injected 2001 won't start! No spark on starboard engine

The nice thing about twin engines is that it provides a very handy source for known good parts.

On my boat the engine won't crank unless the XMSN is in neutral, but maybe yours won't spark.

The absence of spark could be caused by the computer, wiring, RPM feedback sensor or TDC sensor, plus a handful of other parts, like coil, wires rotor and cap.
 

Don S

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Re: Mercruiser 8.1s fuel injected 2001 won't start! No spark on starboard engine

Didn't by some chance knock the kill switch lanyard off did you?
Does the fuel pump run for 2 seconds when you turn the key to the run position?
 

danvoyer

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May 6, 2006
Messages
10
Re: Mercruiser 8.1s fuel injected 2001 won't start! No spark on starboard engine

Thanks for the responses, the engine won't crank at all if it's not in neutral, I've tried removing the gray wires(signal) from the tach but that still did not allow it to start, I have a coil pack for each cylinder and none of them have spark. The boat doesn't seem to have a kill swith lanyard, at least not anywhere where I can find one, there are no buttons or place for the switch at the helm, unless the engine has the connection for it and it's messed up in the engine compartment.
The fuel pump does run when the switch is turned on, and the engine alarm sounds as normal.
thanks
 

Don S

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Re: Mercruiser 8.1s fuel injected 2001 won't start! No spark on starboard engine

Going to need the engine's Mercruiser serial number.
 

danvoyer

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May 6, 2006
Messages
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Re: Mercruiser 8.1s fuel injected 2001 won't start! No spark on starboard engine

It's serial # is OM026165 it has velvet drives serial #4142
thanks
 

Don S

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62,321
Re: Mercruiser 8.1s fuel injected 2001 won't start! No spark on starboard engine

Well, I don't have much experience with the 8.1, but here is the manual you can download for troubleshooting. Perhaps it will help. You will need a scan tool to check things out since you have already checked the fuses and relays.
http://www.4shared.com/office/oLUPo34E/33_555_Dia_BBC_00-08.html?
 

danvoyer

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May 6, 2006
Messages
10
Re: Mercruiser 8.1s fuel injected 2001 won't start! No spark on starboard engine

Thanks for all the info and help, I did all the troubleshooting in the manual and still it didn't work. I now have brought it to a local marina who supposedly has a person familiar with these engines.....

I appreciate all the help!
 

danvoyer

Cadet
Joined
May 6, 2006
Messages
10
Re: Mercruiser 8.1s fuel injected 2001 won't start! No spark on starboard engine

Well, they managed to fix the boat! It turns out it was completely unrelated to the impeller change. It ended up being the crank position sensor, a piece that I had swapped from the port engine and tested but it didn't start for me. According to the mechanic I didn't crank it over enough for it to start.
I appreciate all the help, now i'm finally back on the water!
 
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