pe90 running rough intermittently

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jetskijames
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pe90 running rough intermittently

Post by jetskijames »

just picked up a pe90 with o-470 conversion and pacemaker ignition boat. was sold to me as fouling plugs. i threw champion d21’s in. fired right up no throttle in the yard, get to the ramp and boat wouldn’t fire. good ol ether fixed that. while the motor was cold it would miss randomly and guaranteed at about 1500 rpm. wide open it was fine. after riding for 20-30 min it wouldn’t go over 2100 rpm. if you tried it misfired and shaked really bad. shooting flames and leaving raw fuel soot on back of hull. shut it off to check it out and noticed ground on battery was extremely hot. tightened that up, took off full power ran great then right down the trail same 2100 rpm situation. pacemaker is fairly new and carb looks okay from visual inspection. i am running a brand new holley electric pump and 93 pump gas. where would you start? was hoping to be on the water this weekend. thanks in advance!
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Slidin Gator
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Re: pe90 running rough intermittently

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Bad grounding will eat up any electronic ignition system for sure. The symptoms described can also be due to intake/vacuum leaks, a stuck float or blown power valve.

First thing I would do is spray all your intake and carb system down with the rest of that ether to see if you have any vacuum leaks.

Next you can test the coil packs by bank, similar to a mag drop test, just don't try switching with the prop spinning. On the stern end of each coil pack bank (port & stbd) you will find a connector. Disconnect each bank one at a time and run up the engine to test each 3 coil bank. If a coil is bad it takes out one spark plug from each of two cylinders. It is hard to tell if you loose a single coil as each of those cylinders would still have a plug firing. The issues described would require at least one coil from each bank to fail, which is certainly possible with bad grounding.

Next I would use a spark tester on each plug.

Finally pull all plugs and inspect. Some might say do this first, it's an option. Is it just specific cylinders fouled, fouled in top/bottom pairs or all of them?

Black smoke means excessively rich. What carb are you running? What's your fuel pressure at the carb?

If you haven't narrowed it down by then and still suspect the ignition, give the folks at Pacemaker a call, they are plenty helpful.
I still think I-10 is the Mason Dixon line.
2013 Mike Stossel Boats, 13' x 7' deck over, IO-540, 74" NGQ less winglets.
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John Fenner
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Re: pe90 running rough intermittently

Post by John Fenner »

New Holley electric pump, what is the fuel pressure? Voltage spike could be over spinning the pump and causing too much pressure and the hot ground as well, had same problem on a hotrod I bought.
I never finish anyth,,,.
jetskijames
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Re: pe90 running rough intermittently

Post by jetskijames »

tested for leaks and it’s all tight. got ahold of daren with pacemaker and described my situation. we retarded my timing some. testing the boat out tomorrow will report back!
jetskijames
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Re: pe90 running rough intermittently

Post by jetskijames »

John Fenner wrote:
Mon Sep 13, 2021 12:46 pm
New Holley electric pump, what is the fuel pressure? Voltage spike could be over spinning the pump and causing too much pressure and the hot ground as well, had same problem on a hotrod I bought.
it’s the holley 4-7 psi above the tank mounted
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Slidin Gator
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Re: pe90 running rough intermittently

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jetskijames wrote:
Mon Sep 13, 2021 6:47 pm
John Fenner wrote:
Mon Sep 13, 2021 12:46 pm
New Holley electric pump, what is the fuel pressure? Voltage spike could be over spinning the pump and causing too much pressure and the hot ground as well, had same problem on a hotrod I bought.
it’s the holley 4-7 psi above the tank mounted
James,
Is that 4-7 PSI pressure confirmed via a gauge or just the pump specs?

If pressure is too high and/or float seat pressure too low, the float can open up intermittently and flood the crap out of a motor.

I just got done ordering $100 worth of carb, fuel pump, filters and crap for my lawnmower with similar symptoms, it was spewing raw fuel out the muffler (thank goodness it was hanging over the neighbor's lawn at the time). I put my spark tester on one of the two cylinders and it sparked. I put the plug wire back on and cranked her while tapping on the carb with a hammer. Eventually she leaned out and fired up. Based on that I know it needs a new float seat in the carb and just went all in on the whole fuel system.

Fuel system issues seem most likely in this case.
I still think I-10 is the Mason Dixon line.
2013 Mike Stossel Boats, 13' x 7' deck over, IO-540, 74" NGQ less winglets.
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John Fenner
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Re: pe90 running rough intermittently

Post by John Fenner »

Gator, it likely just needs the Oring on the seat assembly replaced.
I never finish anyth,,,.
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Slidin Gator
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Re: pe90 running rough intermittently

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John Fenner wrote:
Tue Sep 14, 2021 10:19 am
Gator, it likely just needs the Oring on the seat assembly replaced.
That's a Roger John, but then the next thing breaks. My MO usually involves throwing a C note at any problem and focus on the ones $100 don't fix. If I don't do that I'm always fixing things.

Sometimes it takes $200 to fix the missus. :lol: :lol: :lol:
I still think I-10 is the Mason Dixon line.
2013 Mike Stossel Boats, 13' x 7' deck over, IO-540, 74" NGQ less winglets.
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Slidin Gator
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Re: pe90 running rough intermittently

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jetskijames wrote:
Mon Sep 13, 2021 6:46 pm
tested for leaks and it’s all tight. got ahold of daren with pacemaker and described my situation. we retarded my timing some. testing the boat out tomorrow will report back!
James,
What did you find out?


On my end, the lawnmower trouble shooting didn't work out so well, but my MO came through with flying colors. After the new carb, gaskets, fuel and air filters arrived I put them on but the engine kept loosing power under load like before. UPS dropped off a pair of NGK plugs today and I threw them in, got the whole lawn mowed this afternoon, it needed it. New plugs are always part of the first C Note worth of trouble shooting on anything that runs them.
Slidin Gator wrote:
Tue Sep 14, 2021 4:36 pm
John Fenner wrote:
Tue Sep 14, 2021 10:19 am
Gator, it likely just needs the Oring on the seat assembly replaced.
That's a Roger John, but then the next thing breaks. My MO usually involves throwing a C note at any problem and focus on the ones $100 don't fix. If I don't do that I'm always fixing things.

Sometimes it takes $200 to fix the missus. :lol: :lol: :lol:
I still think I-10 is the Mason Dixon line.
2013 Mike Stossel Boats, 13' x 7' deck over, IO-540, 74" NGQ less winglets.
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