Loss of power (approx 1000rpm)

[Mike Ratko]

Fellow boaters....

I have a 2001 Nitro 882 with a 175 Opti on the back. It has run flawlessly since until last week.

I usually used Optimax oil but that was not available so I used Quicksilver DFI oil. There was about 2" of oil left in the reservoir when I added the gallon of DFI oil.

Since then, the hole shot is terrible. It is more like a hole dribble and the top end is 50mph at around 4500rpm. I usually get 60+mph at 5500rpm and a lightning fast 2-3 second hole shot.

Could the performance be due to the oil change? I have not changed the spark plugs since the boat was new. I have attached a few pics of a couple I took out. I use Quickkleen in every tank of gas.



Thank you in advance for the suggestions and ideas.

Mike

 

[AirForce]

No, the oil is interchangeable. Plugs should have been changed a long time ago (just my opinion)

 

[AirForce]

A good starting point would be to check the BASICS:

-Compression Test
-Spark Test
-Fuel Quality, Delivery, and AIR/FUEL PRESSURE TESTS*

*Air and fuel pressures should be checked at:

-Idle
-Under Acceleration
-5/10/15 seconds after engine shutdown

Also, make sure you're up to date on your ANNUAL Maintenance:

Recommended Annual Maintenance for Optimax Engines

 

[Mike Ratko]

AirForce,

Thank you for the reply and comprehensive check list. I ordered new plugs but won't have them until Labor Day weekend. The annual checklist is pretty up to date. I am due to change the water pump impeller and lower unit gear oil in the fall.

It was strange that one weekend all was well and the next - it was crappy. One other thing came to mind since the original post. The o-ring around the fuel cap broke and there is not a good seal. On a car engine, the computer will throw a check engine light. I don't suppose the pressure of the fuel tank is monitored by the SmartCraft system is it? A new o-ring is in my pocket and will be replaced tonight.

I will pick at away at the items one at a time and test the performance. I would like to know the root cause so I can monitor it more closely in the future.

Thanks again for your help.

Mike

 

[Dan J.]

The plugs pictured don't really look too bad from here. I'd hit them with a wire brush and take a piece of fine sandpaper folded up to snugly fit in the gap giving it several strokes back and forth to clean off the corrosion from the center electrode and the ground. Wipe them off good, spin them back in, and see how she runs. If she's back to square, put in the new plugs properly gapped and save the old ones in the boat in case a plug fouls on the water.

The o-ring should make no impact with your description other than possible water intrusion, but your built in water filter on the Opti should take care of that, if any water snuck by. (The oil is pumped, fuel is drawn.)

Air Force's previous checklist is a good rule to follow when diagnosing a problem like this. Good luck!

 

[Mike Ratko]

The engine is still running rough even after I cleaned the plugs and gapped them to 0.043" (NGK PZFR5F-11's). After further reading of a few forums, I am having a good look at the oil system - especially since this issue started right after adding new oil to the reservoir.

I found a crack on the small piece of hose that goes from the inlet oil filter to the on-board reservoir. I am going to change that out and the oil filter and flush out the oil line. After that, I guess I go upstream to each of the oil delivery lines. New plugs are going in after Labor Day. I hope to be in the water in couple weeks with a favourable update.

Mike

 

[AirForce]

Lets us know. I know cracks in the oil line can induce air/loss of suction/feed.

 

[Mike Ratko]

I will. You wouldn't happen to know the i.d. Of the oil line (the black one with the blue stripe)?

 

[THOMMO59]

I agree to do a thorough check, even down to gearbox oils and crap jammed in behind the prop. My opinion on thos plugs is throw them away and grab a fresh set.

 

[Mike Ratko]

I finally got around to replacing the plugs and even the inline oil filter and the weather cooperated for a couple hours this weekend to test things out. I got my 1000 rpm's back and the hole shot is down to 2 seconds. I don't know if it was the plugs or the oil filter but I live by the 80/20 rule and 80% or more was probably the plugs. And the best part was that I was catching fish too!

Thanks for all the help.

Mike

P.S. The ID of the oil supply line is 1/4"

 

[Ron Himmelreich]

Glad you got your Optimax back up to speed. I would replace those plugs every year...at least every other year. A couple of other recommendations:
- Have you changed out your fuel lines since new?
- Have you had your fuel rails serviced?

Ethanol in fuel will deteriorate you fuel lines and plug up filters and fuel pumps. It is an easy job and not expensive. Servicing your rails will help keep your Optimax running well and IMO is a required preventative maintenance item. If an injector gets clogged, it can lean out a cylinder and worst case you blow a power head. European Marine (Don Weed) is who did mine and I HIGHLY recommend him. I had one bad injector and several others that were not flowing properly. You can remove the rails, ship them to him. It is another easy job. Since you now know how to remove the cowling, both these jobs are easier than that lower bolt!!!

RH

 

[Mike Ratko]

Thanks for the advice Ron. I will look into it. I will have to find a good shop here in the Montreal area - things have a tendency to get lost moving across the border.