Boat

Have Boat Questions? Ask a Boat Repair Expert.

Ask an Expert,
Get an Answer ASAP!

I have a 99 mercury 50hp bigfoot 4 stroke. It has a miss on…

Customer Question
I have a 99 mercury...
I have a 99 mercury 50hp bigfoot 4 stroke. It has a miss on #1 mainly at idle, it seems like it goes away after I raise the rpm. I changed plugs, ran fuel cleaner, did a compression check, 125 at all cylinders. When I pulled the plugs #1 looked wet compared to the others but I have spark at that cylinder. I'm at a loss
Submitted: 9 days ago.Category: Boat
Show More
Show Less
Ask Your Own Boat Question
Answered in 4 minutes by:
7/11/2018
Marine Mechanic: Charles, Marine Mechanic replied 9 days ago
Charles
Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 4,743
Experience: US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
Verified

Hello, my name is***** will assist you.

Do you have the serial number for the engine?

Ask Your Own Boat Question
Customer reply replied 9 days ago
0g79b167
Marine Mechanic: Charles, Marine Mechanic replied 9 days ago

Thanks,

Has any work been done to the carbs or its linkage?

Ask Your Own Boat Question
Customer reply replied 9 days ago
Not that I'm aware of. The engine was pulled off a different boat and I put it on mine.
Marine Mechanic: Charles, Marine Mechanic replied 9 days ago

How did you check it for spark?

Can you look at the screws that are touching the throttle arm on the side of the carb. There should be yellow paint on them. Can you tell if this has been disturbed?

Ask Your Own Boat Question
Customer reply replied 9 days ago
No yellow paint anywhere, long gone
Marine Mechanic: Charles, Marine Mechanic replied 9 days ago

Ok, I am betting that it has also been adjusted on, to properly set up the carbs you need a vacuum tool that can screw into the plugs on the intake. With your engine running good everywhere but idle speed, and only on the top carb, that tells me that it needs to be synced. You could try to back off the screw just a bit to see if the engine will pick up that cylinder, but this may throw the others out of their settings.

Ask Your Own Boat Question
Customer reply replied 9 days ago
I will have to try that, I don't have it hooked to water. I may just have to take it to a professional. But from top to bottom what should coil numbers be
Marine Mechanic: Charles, Marine Mechanic replied 9 days ago

They are numbered from the top. 1234 going down.

Ask Your Own Boat Question
Customer reply replied 9 days ago
the top coil that is number 1 should go to #1 cylinder?
Marine Mechanic: Charles, Marine Mechanic replied 9 days ago

There are only 2 coils on the engine correct?

Ask Your Own Boat Question
Customer reply replied 9 days ago
That is correct, my coils from top to bottom are labeled 2314 and correspond with those cylinders
Marine Mechanic: Charles, Marine Mechanic replied 9 days ago

That is correct.

Ask Your Own Boat Question
Customer reply replied 9 days ago
Ok I wasn't sure if maybe the plug wires were mixed up and that might have been the miss
Marine Mechanic: Charles, Marine Mechanic replied 9 days ago

Each plug wire should have a sticker onto which cylinder it belongs. The top coils is 2 and 3, and the bottom coil is 1 and 4.

Ask Your Own Boat Question
Customer reply replied 4 days ago
I played with the carb adjustments with no change. I going to order new coils and see what that does. The tach has stopped working a couple times so I was wondering if it was a rectifier?
Marine Mechanic: Charles, Marine Mechanic replied 4 days ago

With the tach going out like that, it does get its signal from the regulator. That wold also cause a running issue on the engine due to low voltage.

Ask Your Own Boat Question
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a marine mechanicLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask Charles Your Own Question
Charles
Charles
Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 4,743
4,743 Satisfied Customers
Experience: US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.

Charles is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

He answered my question promptly and gave me accurate, detailed information. If all of your experts are half as good, you have a great thing going here.

DianeDallas, TX

< Previous | Next >

Meet the Experts:

Dominick

Dominick

Marine Mechanic

1,009 satisfied customers

25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified

Ted G.

Ted G.

Rigger, Diagnostician

703 satisfied customers

40 years boating, Safe boating instruct., Offshore Race promoter, Failure Analysis, Expert Witness

John White

John White

Marine Mechanic

306 satisfied customers

11 years experience working on outboards, inboards, sterndrives & pwcs

Jason

Jason

Marine Mechanic

16,838 satisfied customers

Degree in Marine Technology. Gas and diesel marine mechanic.

Tan

Tan

MerCruiser Certified Technician

11,179 satisfied customers

40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.

Jeff G.

Jeff G.

Marine Mechanic

4,728 satisfied customers

42 years experience, Certified Master Technician, All Major Outboards, Sterndrives, Hi-Performance

Captain Dave

Captain Dave

Marine Mechanic

2,672 satisfied customers

USCG Licensed Captain, 20+ Years Boating, Fishing, Maintenance and Repair Experience

< Previous | Next >

Related Boat Questions
I have a 2007 60hp Merc 4 stroke. It has a rough low idle
I have a 2007 60hp Merc 4 stroke. It has a rough low idle that doesn't go away after it warms up. The mototr seems to run fine at speeds above 2000 rpm and higher while in gear. The shop I took it to … read more
Shane
Shane
Technician
High School or GED
1 satisfied customers
Number 3 and 4 cylinder problem. replaced injrctors and the
number 3 and 4 cylinder problem. replaced injrctors and the plugs burn black and has a very bad idle. compression is number 1 165 number 2 165 number 3 130 number 4 125. do i have a vale problem. pull… read more
Jason
Jason
Marine Mechanic
Vocational, Technical or Trade Scho
16,838 satisfied customers
I have a 2003 50 HP Mercury Bigfoot motor on a 20 foot
I have a 2003 50 HP Mercury Bigfoot motor on a 20 foot pontoon boat. In neutral it will rev up to 6,200 RPM and set off the alarm. It idles smoothly at 800 RPM. On the lake under load (2 people) the m… read more
Charles
Charles
Marine Mechanic
Certified Mercury Tech
4,743 satisfied customers
I have a 1992 50hp 4 stroke bigfoot mercury outboard engine.
I have a 1992 50hp 4 stroke bigfoot mercury outboard engine. Carbs have been rebuilt, good gas that is treated with stablt. The engine runs great under power. The engine dies in netural in port trying… read more
Charles
Charles
Marine Mechanic
Certified Mercury Tech
4,743 satisfied customers
Charles, I have a 75hp mariner 3cyl that is fouling plug
Charles, I have a 75hp mariner 3cyl that is fouling plug three. just rebuilt the carbs and changed out the plug, wire and coil pack. My gas bulb seems to be getting soft could that cause the third cyl… read more
Tan
Tan
MerCruiser Certified Technician
Certified Marine Technician
11,179 satisfied customers
My 1997 125 mercury starts fine, will idle fine but when I
My 1997 125 mercury starts fine, will idle fine but when I rev it up and return to idle, it has a miss and backfire. it seems to be from the second cylinder from the top. this cylinder also had a low … read more
Jason
Jason
Marine Mechanic
Vocational, Technical or Trade Scho
16,838 satisfied customers
I have a 1982 50hp mercury engine. When I start it after warming
I have a 1982 50hp mercury engine. When I start it after warming up it will not idle in the neutral position. When I pull it back to engage forward or reverse it will stall often with a slight pff of … read more
K. Kergan
K. Kergan
Inboard/Outboard Mechanic
Vocational, Technical or Trade Scho
1,031 satisfied customers
I HAVE A 2001 MERCURY OUTBOARD 50HP BIGFOOT THAT HAS A ENGINE
I HAVE A 2001 MERCURY OUTBOARD 50HP BIGFOOT THAT HAS A ENGINE MISS THAT STARTS ABOUT 2600 RPM. I HAVE REPLACED SPARK PLUGS, FUEL FILTER, IGNITION COILS & WIRES. I RUN OUT ALL OLD GAS AND REPLACED WITH… read more
Charles
Charles
Marine Mechanic
Certified Mercury Tech
4,743 satisfied customers
40hp Mercury o/b---loads up & will stall @ idle. It has
40hp Mercury o/b---loads up & will stall @ idle. It has 2-stroke oil injection system, I accidentally ran it on a 40:1 mixed fuel on top of the injection, cause I ran out of the inboard tank of regula… read more
Jeff G.
Jeff G.
Marine Mechanic
Vocational, Technical or Trade Scho
4,728 satisfied customers
Have an 87 Mercury Classic 50 (45 HP). After about 6 years
Have an 87 Mercury Classic 50 (45 HP). After about 6 years of storage put in a new water pump impeller. A needle valve was stuck in one of the carbs and wouldn't start. Had the carbs bebuilt, new prop… read more
Jason
Jason
Marine Mechanic
Vocational, Technical or Trade Scho
16,838 satisfied customers
I have a 1997 60 hp mercury bigfoot 2 stroke engine. I will
I have a 1997 60 hp mercury bigfoot 2 stroke engine. I will bog down occasionally at 3200 rpms and stall out. I will run under 3200 rpms fine and idle great.… read more
Jason
Jason
Marine Mechanic
Vocational, Technical or Trade Scho
16,838 satisfied customers
I have a 20 year old Evinrude 50hp outboard on my 14 metre
I have a 20 year old Evinrude 50hp outboard on my 14 metre fibreglass boat. The carburettors have been cleaned thoroughly and the engine is correctly displacing water. It revs at high speed ok but wil… read more
Jeff G.
Jeff G.
Marine Mechanic
Vocational, Technical or Trade Scho
4,728 satisfied customers
I have a 15 HP Mercury 2 stroke o/b Idles real bad must
I have a 15 HP Mercury 2 stroke o/b:: Idles real bad must have idle up high to run. While running with ear muffs on I pull #1 spark plug wire off and motor has no change. pull #2 off motor stalls inst… read more
Jeff G.
Jeff G.
Marine Mechanic
Vocational, Technical or Trade Scho
4,728 satisfied customers
What would cause a 1994 112 HP Johnson to suddenly experiece
What would cause a 1994 112 HP Johnson to suddenly experiece a dramatic loss of power, run rough, and fail to fire on one cylinder? Spark appears good to all plugs but #1 is wet after runnig, the rest… read more
shane j forrest
shane j forrest
Vocational, Technical or Trade Scho
270 satisfied customers
Hey John I have a 1998 Merc tracker 125, og014646. the
Hey John I have a 1998 Merc tracker 125, og014646. the engine is not runnig on the lower 2 cyls, comp check 65 psi on all cyls have spark, checked carbs clean and nozzles clear, I have sprayed fuel in… read more
John White
John White
Marine Mechanic
Vocational, Technical or Trade Scho
306 satisfied customers
I have a 1978 mercury 500/50hp. motor runs good but after it
I have a 1978 mercury 500/50hp. motor runs good but after it warms up it stalls when going from neutral to forward, unless I go real fast on the remote. at first I thought it might be the cables were … read more
shane j forrest
shane j forrest
Vocational, Technical or Trade Scho
270 satisfied customers
I have a 50HP 4 stroke mercury motor. When I open the throtel
I have a 50HP 4 stroke mercury motor. When I open the throtel it will not go above 3000RPM. When I put the boat away it smelled like gas. What do you think I should do.… read more
ROCKET
ROCKET
MASTER CERTIFIED TECH
Vocational, Technical or Trade Scho
426 satisfied customers
mercury 50hp (F50 ELPT). 96 model. 4 stroke. just serviced.
mercury 50hp (F50 ELPT). 96 model. 4 stroke. just serviced. misses on top cylinder at 3000-4000 rpm. new carbs etc. tried switching plugs leads etc, no difference. could it be cdi/stator fault?… read more
ROCKET
ROCKET
MASTER CERTIFIED TECH
Vocational, Technical or Trade Scho
426 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x