260 missing at 2500 to 3500rpm

[espen]

Hi !
Had this problem temporarely a few days a go, the engine lost power and was missing between 2500 rpm and 3500 rpm a little more trottle and revs and it run right , seems strange to me...
what can it be ?

[SPECTRE racing]

hi i would check compression and if good check the reeds. does it idle funny? i would also check fuel psi should be at least 39 psi.

[espen]

Hi Spectre racing !
Thanks for reply . Probably vise to check the reeds and the compression.
It idles pretty good and the missing problem did go away for a while then it came back not so strong....strange..

[us1]

Its sounds electrical to me. Most likely in the ignition system. Put timing light on each cylinder and try to get it to miss on the hose. You might even go out and run it with the timing light on one wire at a time until you find the miss. Intermittent electrical problems are not easy to find.

[300drag]

Check all of the ground wires I had the same problem and it was a bad wire.

[espen]

Thanks John and 300drag !
I did feel confident about it beeing a electrical fault and did take a look on the viers to day, did find a red splicing in the main vier system that should be insulated , the insulation was gone and halfe the end splicing where gone because of grounding and eroding from sparks. It was loose just beside the switch boxes , think the sparks that was created could play some havock with the injection or spark.
Hope that was all and that the rectifier and rest of the system didnt burn because of this.
Thanks a lot both of you.
Espen

[us1]

Arcing is pretty bad for the EFI box. I hope its OK.

[espen]

Yes , thanks again John.
Going out on thursday with the boat to drive a some executives to a meeting , hope it works , it did work until the end and got better after a while....

[espen]

Hi !
Did 93 miles with the boat to day , worked great:D until last 20 miles , started to act up realy wierd and worse than before , the engine shut of ,had to stop and rev the engine in neutral and in gear an rev it up passed 4500rpms there it worked realy strong, perfect idle , a little trottle and it seems like it leaned out and had to pull the trottle to idle again to make it run. Idle or over 5000rpm and the engine run great....:confused:
The voltage regulator had losened up and tutched the flyweel and I tought maybe this had something to do with the problem but when I disconected it same problem, checked the teas for the vacum hose for the ecu and was good, swapped ecus with the other engine , and the engine worked ..... maybe it will come back...
The coil in viers from swich box was lying on top of coil high tension outlet can this have something to do with it ?
I had a loose propeller, the trust washer was worn in the cone and made some scratches on the end of the carrier. The trust washer are not made from stainless seems like brass as on the other engines , is this ok ?
thanks.
Espen

[Markus]

I had a loose propeller, the trust washer was worn in the cone and made some scratches on the end of the carrier. The trust washer are not made from stainless seems like brass as on the other engines , is this ok ?
thanks.
Espen

It sounds like you need a new thrust washer and need to make sure that you torque the prop nut properly. You might need a new prop nut as well if it is worn out and comes loose. Do you use the tabbed washer?

[espen]

Hi Markus ! Thanks for reply , yes ,new washer /nut and it was ok again.
The world of high performance are not a resting place....
Swapped the ecus yesterday and everything was ok , after 10 miles it was ok to day to , but then the other engine started to act the same way as the other yesterday. Great idle and great from 4800 up . On the way home it worked like it should again.....
Seems like the ecu are bad , thinking of what to do ? 2 new PCUs ? Expensive.... Buy or borrow a old digital ecu ? Do you have one Marcus ?
Send the ecu to repair or try fix it somewhere in Norway ,Sweden ?...
After a 94miles straigt the Livorsy RPM stopped at 4000rpm and there it is .

[Markus]

Buy or borrow a old digital ecu ? Do you have one Marcus ?


No. My only spare is an old analog ecu. And I am not letting go of my PCU... :)

[espen]

Thanks Markus.
I have an analog ecu myself I dont know if I dear to use it .
How will you describe the difference going from analog to PCU ?
Espen