Optimax misfire

[Razorbill RIBs]

One for the techs if anyone could help?

225 opti with misfire at idle decreases slightly with revs but there.... No smart craft / DDT codes.

Compression on all 6 cyl excellent

80 & 90 psi respectively on air and fuel rail...

Misfire on #2
Ht lead good / swapped out
Coil driver good /swapped out
Coil good / swapped out
Air injector good / swapped out
Fuel injector good / swapped out
All cables from ecu through to all cyl good resistance / continuity
Fuel tracker valve visually good
Cannot check / repair valves on port rail, but as before pressures read good
Reed valves okay with bore scope, but next job is to remove plenum and fully inspect....

Any other ideas / suggestions before we do please?

Running out of ideas : thumbs:

Thanks in advance!

[Portholme]

I've not had the same issue but have the same engine. I was told the plugs need replacing frequently. Have you tried that??

[Razorbill RIBs]

Originally Posted by Portholme

I've not had the same issue but have the same engine. I was told the plugs need replacing frequently. Have you tried that??

Sorry, didn't mention.... New plug set was first thing we did

[Portholme]

Yes and you did say one for the techs. And that's not me!!

[Razorbill RIBs]

Damaged reed valve on that cylinder is the culprit, close inspection shows another on the way on a second bank! Excellent compression and no visual damage in the cylinder so think we should be good to just replace....

Anyone else experience of these failing in the 225? Read about 250 batch which had problems, but that was the screws having not been fixed properly in the factory!?!

[Searider]

Dan,

I have a commercial customer who had reeds fail on a relatively young but high hours 225 Opti.

Duncan

[Razorbill RIBs]

Thanks Duncan, I'm keen to understand if it's a common fault and if an alternative material may be better.... Anyone have any suggestions?

[Searider]

I've heard that Boysen (sp?) composite reeds can be a good alternative.

The boys on boatmad should be able to help.

[Jeff]

Have a search on Bass Boat Central ,,, bbcboards.net forums . The mercury section has quite a bit on replacement reeds. USA of course but useful nonetheless. Boysen don't appear to be favoured but who knows 😊
I think the later opti pros have fibre reeds as standard.
I do wonder about changing mine as a precaution/maintenance item (like the compressor!) but not sure how complex it is. Just on 860 hours and don't want a blown engine

Cheers

[Daniel]

How many hours on this engine; out of interest?

[Razorbill RIBs]

There's only 40 ish hours on the powerhead Daniel.....but the rest if have engine was at 800hrs....it looks like three reed blocks were replaced when it was fitted (as the old ones were found to be chipped!?!... I have them here) of most concern is that one of the the 'new' ones has a chip, although it is an old one which has split causing the misfire....

Either way, I'm not impressed with them. After quite a but if reading I'm probably about to order two sets of these from the US. Good reviews and wouldn't cause damage if they fail.... Will have to run with the mercury replacements for now due to lead time (risk it?!?) and swap these out over winter.

The price difference is ridiculous! Just 135 usd per engine plus 20usd for gasket (90usd shipping etc)..... Compare that to £110 plus vat per set (6 of per engine) and £40 odd for gasket from Barrus!

[Razorbill RIBs]

Oops forgot link Chris Carson Marine, Manufacturer of custom reed valves for all outboard applications.