6cta 8,3 Idle drooping

[james]

I’ve got 8,3’s rated at 400 hp with the Nippon Denso pumps.  Engines are in good running order, but I’ve got a small frustration.  On my port engine the idle drops from 750 to around 500 when I put it in gear.  This worries me that I might get a stall at exactly the wrong moment while docking.

Any help on how to correct this would be appreciated.

Topic

[james]

Thanks Tony, I’ll give this a try during the week.  Will be sure to get the engine reasonably warm prior to the attempt.

[Tony Athens]

Sounds like a “classic” symptom—–you need a bumper spring adjustment or possibly (not that likely) a different bumper spring.. How long has it done this?– Ever done an adjustment?   You need to refer to your O&M Manual and adjust your bumper spring..In this period of engines, a few of them even required a change of bumper springs (a different number or sping rate, like #16,#17, #18 , ??) to settle the engine down..    

 

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Just found a copy I made years back…………

 

Tony

[james]

I don’t have fuel coolers, and the problem seems a bit more pronounced when we come back in.  However, I doubt fuel temperature as it is only on one engine not both.  Tanks are 173 gallons each and I usually keep them around 3/4 full.  Was thinking it might be the bumper spring, I’m not sure what the full function of the bumper spring is on the pump.

[Rob Schepis]

Does it behave the same when you first head out compared to when the fuel is hot?  Do you have fuel coolers?

[Author]

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