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F115 Yamaha 4s: "Bogging down"
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| Phil T |
Posted on 04/19/08 - 4:03 PM
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I have a serious issue with my 2003 Yamaha 115. The engine is an inline 4 cylinder with fuel injection. 106 hours.
Last fall I noticed it ran a bit "rough" at ~1900 rpm. It would disappear slightly below or above that RPM.
No other issues last year.
Prior to running it this year I changed the plugs, new fuel-water seperator and engine fuel filter. Running on internal tank full of fuel stabilized gas from last fall. On my season shakedown cruise 2 days ago, started fine, idled fine. Slowly warmed up, got on a plane, cruised at 32-3400 with out issue. After 10 minutes of running I stopped at an island dock for 5 minutes, engine idling.
After leaving the dock and slowly accelerating, it started to "bog down". I could not get on a plane and the engine sounded off, not smooth, like it was not running on all cylinders". In neutral, at 1300 rpm, you could hear it run rough. In gear, with full throttle the engine would not go above 2500. At one point giving it more throttle, it did smooth out for a few seconds, accelerate, then ran rough again. I limped home at low speed. I double checked spark plugs and wires are tight/good connection.
I was thinking of eliminating fuel as an issue by running it on a separate tank of clean gas prior to making the dreaded call to the dealer on Monday.
While I have a shop manual, my skill level on engines is basic. Can change plugs/fluids/fuses.
Any suggestions?
1992 Outrage 17 I
2019 E-TEC 90, Viper 17 2+
2018 Load Rite Elite 18280096VT |
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| oliver1234 |
Posted on 04/19/08 - 5:43 PM
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the "not running on all cylinders", sounds like an ignition problem
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| Joe Kriz |
Posted on 04/19/08 - 5:52 PM
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Phil,
New plugs can be bad. It has happened to me before.
Put the old plugs back in if you still have them and give that a try. This won't cost you anything to try out before spending time and money on the next step in the diagnosis.
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| bobby z |
Posted on 04/19/08 - 8:57 PM
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You may look in you gas tank ,the tank maybe oxion. Cut the fuel filter in half and look for small white parts in the paper, If so all you injectors will need to be changed and in the motor there are two small filters that will have to be upgraded>Bob Zollo
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| Derwd24 |
Posted on 04/19/08 - 9:45 PM
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Very interesting, I'd read about that causing issues before. Good luck and let us know what you find Phil.
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| kamie |
Posted on 04/19/08 - 10:27 PM
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You can always try decarbing the outboard?
Seafoam
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| Phil T |
Posted on 04/20/08 - 7:23 AM
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Update -
Changed back to the old plugs. No difference.
Several of my boater buddies who work on their engines can't help since it is a late model fuel injected engine and not the straight forward 2 stroke carborated engines.
Will drain the fuel line/engine filter and hook up to a portable tank of fresh gas today. While I am very skeptical it is a fuel qualilty issue, it is the only thing left I can do with my limited skills.
1992 Outrage 17 I
2019 E-TEC 90, Viper 17 2+
2018 Load Rite Elite 18280096VT |
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| Derwd24 |
Posted on 04/20/08 - 9:29 AM
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Is this the first issue you've had with the engine since new? One other thing you could try to check and see if it's a vac leak would be to spray just a little fogger (using the thin red tube attachment) at the base of each injector while the engine is running, and listen for a change in idle, which would indicate a bad seal and air leak. Also, the new plugs that you removed, do they all look the same or does one look different from the rest, indicating a problem with one cylinder?
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| Phil T |
Posted on 04/20/08 - 10:01 AM
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This is the first issue with the motor. I run the engine with kid gloves, warm it up every time, no mashing to WOT etc.
I bought the boat in September 2005 and the motor had 32 hours on it. To date I have done the fluid changes and new plugs each year. Plugs bought at the local dealer.
The OLD plugs (still have them) all looked the same, a bit dirty but okay. The new plugs look fine.
Will look at the manual and engine and see if I am up for the fogger test. Got to say this engine is daunting compared to my old Yamaha 90 2-stroke.
1992 Outrage 17 I
2019 E-TEC 90, Viper 17 2+
2018 Load Rite Elite 18280096VT |
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| kamie |
Posted on 04/20/08 - 10:06 AM
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Before you call the dealer try doing the decarb on the engine.
Lets review: You had a slight problem last year before winter layup. you fogged the engine and then let it sit, all winter. You start it up, run ok, until you let it idle for awhile. Now all that carbon, is nice and gooey but not really going anywhere. Engine boggs down, runs rough. Switch back to old plugs, still runs rough, not a happy engine.
Most engine manufactures make some cleaning product to reduce carbon buildup.
Mercury - QuickClean
Yahama - Ring-Free
Generic - Seafoam
Sal's decarb technique
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| Phil T |
Posted on 04/20/08 - 11:15 AM
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Kamie -
I don't have carbs. It is fuel injected. I was on the water till October so didn't fog the cylinders. I ran it in December and February on muffs.
Maybe run some Seafoam/Ring Free from a separate tank?
1992 Outrage 17 I
2019 E-TEC 90, Viper 17 2+
2018 Load Rite Elite 18280096VT |
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| Derwd24 |
Posted on 04/20/08 - 11:30 AM
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Certainly couldn't hurt to try, and if it was a injector issue, some sitting in there overnight may help. Have you had it running since the last outing when it bogged? Could you tell if it were normal or rough running on the muffs? Am wondering if it's an issue that happens when fully warmed up?
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| MW |
Posted on 04/20/08 - 1:38 PM
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I'm skeptical of the fuel quality (even w/ stabilizer).
mw
I'm also thinking possibly a small crack on a plug wire that can't be seen, and is grounding out as the motor climbs in rpm, cracked or faulty wire.
Edited by MW on 04/20/08 - 1:55 PM |
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| Gary Sr |
Posted on 04/21/08 - 4:34 AM
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Really sounds like restricted fuel. Have you checked your primer ball? There might be a problem with the check valve inside the bulb. Have you checked the vent on your gas tank? Some critter might have built a nest in the screen. Run the engine on a separated tank with a different gasline and primer bulb to the engine. See what happens.
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| wrangler |
Posted on 04/21/08 - 9:15 AM
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My 2004 90HP 4 stroke fuel injected ran great. I had an inline filter in the hose with a glass over screen filter (sold at Boaters World). I upgraded to a fixed screw on canister (size of engine oil filter) type. I had same problems you mentioned. I went back to the inline filter, no more problems. The engine would not draw enough gas thru the canister filter. It was to restrictive.
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| wrangler |
Posted on 04/21/08 - 9:15 AM
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My 2004 90HP 4 stroke fuel injected ran great. I had an inline filter in the hose with a glass over screen filter (sold at Boaters World). I upgraded to a fixed screw on canister (size of engine oil filter) type. I had same problems you mentioned. I went back to the inline filter, no more problems. The engine would not draw enough gas thru the canister filter. It was to restrictive.
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| Gary Sr |
Posted on 04/21/08 - 9:28 AM
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One other thought. When you took the fuel/water separator off did the gasket/o-ring come off and did the new gasket/o-ring seat? I don't think you have a major problem just a little rock in the road that is starving your engine for fuel.
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| egerrity |
Posted on 04/21/08 - 9:39 AM
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My money is on a fuel problem. I hope its something very simple.
Ed
1991 Montauk 17 - 2012 ETEC 90HP |
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| TexasOutrage |
Posted on 04/21/08 - 2:29 PM
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I am awaiting the verdict on this one since I am running twin 150 fourstrokes.
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| Phil T |
Posted on 04/21/08 - 5:05 PM
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Let me say, I really appreciate all of your advice and support with this.
Today I drained the fuel system and ran the engine on portable tank with clean gas. No joy. Have reviewed fittings, filter for any leaks.
I posted my symptoms on the Yamaha forum of I-Boats and Rodbolt (a Yamaha Master mechanic) suggests the cause is "..most likly gonna be a clogged filter on the high pressure pump or the injector screens are clogged"
I looked at the old water separator filter and bracket that I just replaced. I see lots of rust and crud on the inside of the bracket and ports. I think this may be the source of my problem.
In the shop she goes. Guess I know where my tax "rebate" check is going. Will post results.
1992 Outrage 17 I
2019 E-TEC 90, Viper 17 2+
2018 Load Rite Elite 18280096VT |
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