1997 225 ProMax EFI... bad gas?

[PoonToonBabe]

Running about 5000 RPM and the motor cuts out completely. No warning buzzers. Let it sit for a moment, cranked it and it turned over, but ran rough and made a slight knocking sound. Turned it off and got towed in... Compression showed nothing on #4. Took it to the mechanic who says that #4 and #6 (has shrapnel) need to be resleeved. He doesn't know what caused it as the injectors were sent to Brucato and came back with good results. His plan is to replace most everything, pumps, lines, ect. and drain the fuel... and then dyno test. He suggested that bad fuel might be the cause. It was running on the gas we have used for years, with the exception of 10 gallons of fuel from our local dock (a place we have never purchased from). So, what say you -- could bad gas cause something like this? Also, if we go ahead with the rebuild, from your experiences, do boat shops offer a warranty on the things that are replaced? I don't want to drop this kind of cash and then have it shart the bed again shortly after getting it back on the water.... :nonod: Any helpful input is welcome. Thanks in advance....

[mercrazy]

yes, bad gas will do it. it bet it was supposed to be 87 octane.
most reputable builders will give a warranty if you follow their recommendations.

[njj502]

With ANY failure of ANYthing you MUST determine root cause or.... you will be back in the same situation again. Need to see what kind of failure it was. Did the pistons melt in the top indicating detonation? If so it's either timing or crap gas. What octane were you running? Was 5000RPM the WOT RPM? If so you are running it WAAAYYY too slow. ProMax should be about 6500 at wide open throttle.

Get some pix and post them up. Depending on what the pistons look like it's easier to tell what happened. Make sure the technician KNOWS FOR SURE 100% why the engine failed!

Nick

[TEXAS20225]

since both blown holes were on the same side look at the switch boxs double firing does that exact thing PS KNOW YOUR ENGINE BUILDERS RECORD or be sorry later if your water separator was doing its job it would have alarmed with that much water in the fuel

[Vecman]

Also check and see if you have an A17 ecu. I think that was around the time Merc
had the ecu recall. They were bad about running lean in the mid range rpm's. You
can do some searching on here to get some more info.

[ChrisCarsonMarine]

Your motor stuck from either lack of lubrication,or detonation.
Detonation can be caused by many separate things or a combination of two or more... The common ones...fuel restriction,low octane fuel,dirty injectors/carbs/filters/screens,too much maximum advance,too low max attainable rpm( too much prop or load),overheat,cross firing/double firing,and more...your tech needs to figure out what happened.
Where are you?If you want I can arrange economical shipping if you want to send your complete powerhead to me,I'll break it in on a fully instrumented test boat...fuel pressure,egt's etc,
Not trying to take someone's work away,but if they can't or don't want to try to figure it out...Chris

[TEXAS20225]

Chris Carson is a good candidate for your pmax:thumbsup: good mechanical shop with all the machine shop lots of knowledge and a good history . if i was in his neighbor hood and was a motor rebuilder myself he would get the job:iagree:

[m3mm0s rib]

With today's technology it would have no problem :thumbsup: