1995 Evinrude 90 Hp Bogging Down after 30 minutes on plane

barryvj

Cadet
Joined
Aug 3, 2008
Messages
17
Hi All,

This has been an intermittent problem for almost a year now?and its driving me crazy:mad-new:
I have a 1995 Evinrude 90 Hp (E90TLEOR) 2-stroke, powering a Lund Fisherman 1800. I rebuilt the engine in 2010 after my VR02 oil pump and alarm buzzer failed (newbie).

Here are the symptoms: After running on plane for ~30 minutes, the engine bogs down and will not go over ~3,000 RPM. No buzzers/alarms sound. All operation under ~3000 RPM seems normal. Once it happens, it stays that way until I take it out the next time and I have a ~50% chance that it repeats.
I took the boat out 4 times earlier this season for extended day use with no issues at all. Last week it bogged down and when I got home I check the spark plugs which looked evenly gummed up 'wet', not dry at all.

This is what I've done over the past year to ?fix? this problem through visits to mechanics and a lot of DIY:
? Drained the fuel tank
? Removed and inspected the fuel tank pick-up ? looks fine
? Replaced the fuel lines from tank to engine
? Added a Sierra fuel/water separator (I use Star Tron enzyme treatment religiously)
? Ran a can of Sea Foam in the 26 gallon tank with premium fuel
? Mechanic ?cleaned? carbs
? Replaced the on-board engine fuel filter
? Replaced VR02 fuel/oil pump with single stage fuel pump (I premix anyways)
? Checked compression ? all good and within +/- 5psi
? Purchased a 3 gallon auxiliary fuel tank and switched over when engine bogged down. After 1.5 gallons of fresh
premium fuel was used up, still no change (not a ?bad gas? problem)
? Checked for spark while under load and engine bogging down, it was sparking, but I?m not sure how to tell if it was
good or bad.
? The Power coil and Sensor coil both pass a static resistance test. I plan on conducting a dynamic test on each
(and the ignition coils) over the weekend if it bogs down.

I've been thinking that this is a fuel delivery issue all along, but now I?m convinced it is a power coil, sensor coil, ignition coil or power pack problem. The consistent 30 minutes of flawless operation prior to bogging down sounds like something is slowly heating up and possibly shorting. Along with the ?wet? plugs it seems to point to an electrical problem.

Anything logical that I?m missing?

Thanks for your help!
 

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Rollinunknown

Petty Officer 2nd Class
Joined
May 3, 2010
Messages
105
Re: 1995 Evinrude 90 Hp Bogging Down after 30 minutes on plane

Man those plugs look NASTY! geez... is it still VRO?
 

barryvj

Cadet
Joined
Aug 3, 2008
Messages
17
Re: 1995 Evinrude 90 Hp Bogging Down after 30 minutes on plane

Yeah...the plugs are pretty gummed up. I'm not sure if I understand your question though... I replaced the OEM VRO2 pump with a single stage pump last year. I premix at 50:1.
 

pn

Petty Officer 1st Class
Joined
Apr 20, 2013
Messages
374
Re: 1995 Evinrude 90 Hp Bogging Down after 30 minutes on plane

post after your dynamic tests/
 

barryvj

Cadet
Joined
Aug 3, 2008
Messages
17
Re: 1995 Evinrude 90 Hp Bogging Down after 30 minutes on plane

Sorry for the delay. I wanted to make sure that the fix held as this has been a real challenge to figure out. The electrical testing showed no problems with the coils or wiring. I did notice a bare wire coming out of the main coil under the flywheel and I applied some liquid electrical tape as I could not replace the wire.

So what was wrong? The carbs were contaminated with very fine particles. I had the carbs removed and steam cleaned and I haven't had the problem again after running many times for long hard runs. When I drained the tank I kept the gasoline in spare tanks. I let the gas settle in a clean 5-gallon bucket and was amazed at the amount of particles in the fuel. I siphoned off all but ~3 inches of the fuel taking care not to disturb the particles and put it back in the boat. I repeated this 2 more times to recover most of the gas. I haven't had any problems since.

What amazes me is that the particles made their way through a Sierra fuel/water seperator and an onboard fuel filter. The fuel/water seperator has since been replaced by an ultrafine filter.

After all of this, I don't have an explanation for why the problem would start showing itself after 30 minutes...I was convinced it was something to do with thermal expansion...I guess not.
 
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