1996 Mercury 200 EFI Intermit getting on plane

[Ron454]

Hi,
Reaching out for some assistance. I have a 1996 Mercury outboard 200 EFI serial number 0G337088 that will get on plane sometimes and sometimes it will hit at 2500 ish RPMs and stay when at wide open throttle and while trying to come out of the hole. While trying it will "spike" as if it suddenly gets fuel or something. Then after a couple times spiking it will "catch" and come out of the hole and will run fine. I can run it the rest of the day fishing and it may not do it again until the next trip. I notice if I idle a while it seems to do it more. It doesn't skip, but does idle rough. I think it has idled a little rough for a long while though and well before it started this. It has a fresh fuel water separator, and new spark plugs. The fuel line with squeeze ball is new too. I run ethanol free fuel that is 89 or 87 octane. Both voltage regulators are new and it puts out around 13 volts. The battery is charged to 100%. I looked at wire connections and all seems secure.

I have a video of it doing it I can send over WhatsApp or to an iphone if it helps.

Thank you in advance, Ron

 

[dingbat]

Compression and fuel pressure numbers?

 

[Ron454]

Compression and fuel pressure numbers?

Might be several days before I can get to checking it. I had a new oil pump and drive gear put on it in Aug 2019 and the mechanic said the engine looked good on the inside and the compression was good. Maybe 20 hours have been put on it since, but I can check when I can get a little time.

 

[Mikey N.C.]

Needs a decarb

 

[Mikey N.C.]

My bad , fuel injection

 

[Ron454]

My bad , fuel injection

yup

 

[QBhoy]

Why did it need a new oil pump ? Hopefully your issue isn’t related to this.

 

[Ron454]

Why did it need a new oil pump ? Hopefully your issue isn’t related to this.

The oil pump drive gear stripped and I don't believe it is related since it ran great for several months/trips out after it was replaced. I am thinking it is either the injector drivers in the ECU or the knock sensor. I forgot to mention that I also had carbon fiber reeds put in it when I had the oil pump and drive gear replaced.

I really wanted to see if anyone on here had ever seen this, but it doesn't look like it.

 

[Dukedog]

might take a look at mech fuel pump.. may have trouble keepin' tha vst full all tha time... maybe?

 

[Ron454]

might take a look at mech fuel pump.. may have trouble keepin' tha vst full all tha time... maybe?

I thought that could be a problem, but what gives me pause is it will run great at WOT without issues. When it gets power it is like a switch is kicked on. Thank you for the ideas tho.. I need to run a pressure test on it anyways.

 

[Dukedog]

a pump with "leaky" problems mostly act up at idle (rough, excessive smoke) but will perform as normal at wfo.. jus an idea?.. good luck, hope ya get it figured out soon......

 

[Faztbullet]

Could be switchbox or stator as running on one bank and then kicks in..