The idle relief tube requires removal of the port-lower cowling, and is really something that should be taken care of by the dealer. I have not seen any documented cases of "performance loss" with this, but it does make a notable change in the sound of the engine.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
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Going back tomorrow to get it on the pc and looked into deeper.
From the one I have seen where the idle relief tube came loose, the customer said it "had lost it's growl" at startup (and just sounded different).
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Pencil coil will effect power and rpm. Cheap fix
they lake tested it this week - computer showed no issues before lake test, lake tested "terrible" - said they were going to replace O2 sensor and see if that resolves it (IDK?).
No "pencil coils" on a V-8 model. Could certainly be an ignition coil, plug wire or spark plug, though.Originally Posted by RANGER MIKE Z21
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
replaced O2 sensor today (was a fault on it). will run this weekend to see if it fixed the issues im having - on a positive note it sounded better on the hose (but has been hard to tell until it was truly in the water and immediately on start up i knew it was "off." will see what the next trip brings.
No dice. Still same issue persists. Not sure what to do now. Fuel consumption is excessive, holeshot sluggish, top end down roughly 8-10mph. Zero faults or codes on motor now. Appears to run “good” other than this issue. Just feels like it won’t get up on the pad.
Watching with interest and hoping you get the support you deserve to resolve this
2018 TRX 18. 2020 Mercury 200 Pro XS V8
Adding - fuel consumption has just about doubled (probably closer to 1.5x more than “normal”) based on my history and trails on Lowrance. Not sure what’s left to check. Will reach out to mechanic Monday to review and see where we go from here.
Last edited by jab0914d1; 05-17-2021 at 10:54 AM.
Have the plugs and plug wires been checked? Especially to make certain that plug wires are fully indexed onto the spark plugs and that there is no apparent damage to the wires. One easy-simple check is to clip a timing light to each plug wire, one at a time, while watching for a flashing pattern.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Still living with the issue at the moment. Still runs good but not “right.” Taking it for 300 HR service in a week or so and praying they find something wrong, still no alarms.
Off the wall item, but it might not be a bad idea to get a bore-scope and inspect the fuel line that runs from the fuel filter (through the adapter plate) to the FSM. Primarily the area between the filter and the adapter plate is the area to focus on, looking for evidence of anything impinging on it.
I've seen ONE (and it's not someplace you would normally look for a restriction).
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
How did this turn out? Did they fix it?
Not solved yet. Living with it. Headed in week after next for service to check again. Around 320 hours right now. It’s clear to me the 4S motors don’t like the heat and humidity - at least they certainly have performance degradation more so than the two strokes under similar conditions. I find the 4S is very inconsistent in speed throughout the day, minute by minute, whereas my two stroke would top out and run consistent speed for hours at a time each day. Just different I guess. I’m running a 23p fury 3 blade and peaking around 6k RPMs each day right now for the last month or two - speed in the lower 70s still, not what it should be for sure for where it was. I certainly attribute some of the “sluggish” part to the environment given it was early spring when this problem presented itself and since it has significantly warmed so I anticipate picking up 2-3mph as it cools if my theory on the more severe impact on surrounding environment holds true for these 4S motors. Still runs good and strong just can’t get and more rpms than what I am at now and speed remains challenged from where it was. I could jump on pad and blow past most folks before with the 26p 3 blade fury and now it still doesn’t want to plane off with the 26p
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