twin 225 opti

H

hutch6575

Cadet
Joined
Nov 24, 2003
Messages
12
Good Day Everyone,<br />I have a boat with twin 225 opti's the problem is that when you bring throttle above 4000 rpm's the port engine starts pulsating from 3000-4500 rpms.Had a same problem on same side before and spent many hours with mercury tech. trying to solve problem with negative results. Mercury sent new fully dressed power head and problem went away,but now problem is back after about 300 hrs or 4 months time.It uses same fuel tank as other engine no alarms,or faults. any help will be greatly appreciated.<br /><br />Hutch
 
K

Kiekhaeferscurse

Petty Officer 2nd Class
Joined
Nov 25, 2004
Messages
173
Re: twin 225 opti

Hi Hutch, hate to try and answer a question with a question, but the term pulsating has me confussed (whats new), Have you had a cylinder load test performed at the stated problem rpm range? this test would be done on the water with a DDT to determin wheter or not all 6 are carrying a load?<br />Also when they replaced the powerhead & it ran better did they replace any other items..ie, ICU, fuel pumps etc etc?<br />Cheers
 
H

hutch6575

Cadet
Joined
Nov 24, 2003
Messages
12
Re: twin 225 opti

Hey Kiekhae,<br />Thanks for the reply. we have done u/w test with a CDS with neg results. I have taken snap shots before problem during and after. The new power head that I put on was fully dressed(all new components)The problem with doing the cylinder load test at the rpm range is the engine has a very violent pulsation or surge.Mercury never notified what they found to be the problem with the old power head. Also compression was a little low compared to the book specs but mercury said that would not be the cause of the problem. Any more help or questions greatly appreciated.<br />Hutch
 
K

Kiekhaeferscurse

Petty Officer 2nd Class
Joined
Nov 25, 2004
Messages
173
Re: twin 225 opti

Dont know if this is helps, but this is the way I would tackle it:<br />Mechanical, No Broken reeds. Compression between cylinders 10/15% no 1 cylinder below 95psi, no Metal transfer on plugs, plugs all reading the same. Gear oil Clean with no debris or water (binding gear case)<br />Then I would go to the Fuel:<br />On the water test: Use a Day tank on the problem engine (checking for fuel restrictions from main tank) Still no success, check fuel/Air psi at the rails, pay particular attention to the operation of the tracker valve at the problem rpm area.<br />If you are 100% sure the fuel side checks out, go to the electrical componets, I really dont trust the DDT self tests but (for eg: DDT says Fuel injectors pass, but quite often they are not actually working( Hold your finger on the injector then hit test) you can feel the difference in a bad injector.<br />when your checking out the ignition system, dont forget the battery this is most important have the engine on its own batery (at Least 1000 CCA) no wing nuts Star washers & Nuts, then go from there. Hope this helps.
 
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