Boat

Have Boat Questions? Ask a Boat Repair Expert.

Ask an Expert,
Get an Answer ASAP!

This answer was rated:

I have a 93 mercury force 120 hp it will tach only 3000 rpm…

I have a 93...

I have a 93 mercury force 120 hp it will tach only 3000 rpm then if you hit a wake it will suddenly run fine . Starts good idles fine , compression check is good on all cyl replaced stator, and ignition box, fuel pump

Mechanic's Assistant: Sometimes boat issues seem like they'll be really complicated, but end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Is there anything else the Marine Mechanic should be aware of?

The fuel pump is from a 97 force 120

Show More
Show Less
Ask Your Own Boat Question
Customer reply replied 1 month ago
if after running ok, it reverts to only taching to 3000 rpm after the throttle iis returned to nuteral
Answered in 1 hour by:
6/17/2018
Charles
Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 4,886
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 1 month ago
no the tag is gone

Are all the wires to the switchbox tight in their connections?

Have you looked at the plug boots to make sure that there is not a cracked one that is throwing park out it.

Ask Your Own Boat Question
Customer reply replied 1 month ago
all the wires are tight I do have some concerns about the spark plug boots where they attach to the coils they look like they may have had some sealant applied at one time
Customer reply replied 1 month ago
I suppose I could check the spark at night to see if its arcing

That would be a area of concern for sure and can cause an issue like this. When you hit a wake it can shake the engine and move the wire slightly causing it to make or break contact. You can get them from the attached site. You will need to order 4 of them.

https://www.boats.net/product/mercury/821945T28

Ask Your Own Boat Question

If it is hitting the cowling you would not know unless it is installed. You can shake the engine some to see if it cuts out any. you can actually get shocked by a spark jumping to the cowling, even though it is plastic.

Ask Your Own Boat Question
Customer reply replied 1 month ago
What your saying makes sense , but the boat pounds pretty good at full throttle when it runs , then when you cut back to neutral the same problem 3000rpm
Ask Your Own Boat Question
Customer reply replied 1 month ago
I HAVE A PLUG CHECKER AND IT SHOWS FIRE ON ALL PLUGS AT IDLE

Do you also have a multimeter?

Ask Your Own Boat Question
Customer reply replied 1 month ago
I DO
Customer reply replied 1 month ago
STATOR AND E4 ARE NEW

Ok, either at idle or cranking, test the voltage going to the switchbox on the red wire to ground. It needs to be 25V at idle and come up as the engine speed does.

Ask Your Own Boat Question
Customer reply replied 1 month ago
IF IT DONT

Then the stator is failing. Even if it is new.

Ask Your Own Boat Question
Customer reply replied 1 month ago
GUESS I'LL CHECK THE COILS AND THE STATOR, i HAVE ALL BUT GIVEN UP . WOULD BAD COILS OR COIL CAUSE THE PROBLEM

One bad coil can reduce the RPM down that far. Take them loose and check the grounds on the backside of them. Make sure that they are clean.

Ask Your Own Boat Question
Customer reply replied 1 month ago
THANKS FOR THE HELP , i HAVE ALWAYS BEEN ABLE TO FIX MY PROBLEMS, BUT THIS HAS ME STUMPED
Customer reply replied 1 month ago
tHE MOTOR SAT FOR A WHILE BEFORE i BOUGHT IT TO REPLACE A 97 FORCE THAT BLEW UP

Let me know what kind of readings you get and we can go from there if we need to.

Since it sat, the carbs may need to be gone thru as well.

Ask Your Own Boat Question
Customer reply replied 1 month ago
wENT THROUGH THE CARBS , CHANGED FUEL LINES , FILTERS AND FUEL PUMP

Ok, let me know about the coils and the grounds on them and the test on the stator.

Charles
Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 4,886
Experience: US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
Verified
Charles and 87 other Boat Specialists are ready to help you
Ask your own question now
Customer reply replied 1 month ago
Stator checked ok, have other commitments Tuesday going to check wires to coils and ohm coils Wednesday. I called a Marina they get $128.00 an hour for that I can replace all the coils . What you said makes sense , I have either a bad connection or bad coil I think.

Let me know how the test go.

Ask Your Own Boat Question
Customer reply replied 1 month ago
found the number 3 coil was cracked . thank you for your help Charles

That will drop you several hundred RPM on top and also slow down the holeshot of the boat fir sure.

You are welcome. Do you need the part number for it?

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: 4,886
4,886 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

704 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

17,310 satisfied customers

Degree in Marine Technology. Gas and diesel marine mechanic.

Tan

Tan

MerCruiser Certified Technician

11,264 satisfied customers

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

Jeff G.

Jeff G.

Marine Mechanic

4,729 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
1984 115 hp inline 6. Had carbs rebuilt. wont get above 1500
All fuel line and primer bulb have been replaced also.… read more
Tan
Tan
MerCruiser Certified Technician
Certified Marine Technician
11,264 satisfied customers
Whenever i put my boat in the water and put it in gear it
whenever i put my boat in the water and put it in gear it stalls runs in a tub fine it is an 85 hp force 1986 … read more
Charles
Charles
Marine Mechanic
Certified Mercury Tech
4,886 satisfied customers
1976 black max 175 stator was bad ohm,ed out bad replaced
1976 black max 175 stator was bad ohm,ed out bad replaced stator motor idles well revs in neutral falls flat on its face I changed switch boxes with known good ones, no difference coils ohm out well a… read more
Charles
Charles
Marine Mechanic
Certified Mercury Tech
4,886 satisfied customers
My 200 HP 1986 Mercury outboard motor has recently started
My 200 HP 1986 Mercury outboard motor has recently started to lose power intermitantly. It will suddenly have no power after 3000 rpm and will not go over 3000 rpm no matter how far you push the throt… read more
Charles
Charles
Marine Mechanic
Certified Mercury Tech
4,886 satisfied customers
My 1994 mercury 60hp was running just fine then it went from
My 1994 mercury 60hp was running just fine then it went from running over 3000 on the tach to a little over 2000. Idles and runs until you put the gas to it. Could it be the fuel filter?… read more
Jason
Jason
Marine Mechanic
Vocational, Technical or Trade Scho
17,310 satisfied customers
I have a 40 hp outboard 1993 evinrude motor starts up fine
I have a 40 hp outboard 1993 evinrude motor starts up fine but when accellaration it shakes the motor from side to side it has good compression at 120 psi in both cyl unplugged the temp switch new coi… read more
Tan
Tan
MerCruiser Certified Technician
Certified Marine Technician
11,264 satisfied customers
I have a Force 125hp outboard engine that seems to have a fuel
I have a Force 125hp outboard engine that seems to have a fuel problem. The engine runs fine at 20 mph. When I give it full throttle, the engine runs full for about 10seconds and then sputters, misses… read more
Tan
Tan
MerCruiser Certified Technician
Certified Marine Technician
11,264 satisfied customers
Mercury 200hp hdpi: i have mercury 1999 , 200 hp twins..a
i have mercury 1999 , 200 hp twins..a new problem just started......just had fuel pumps and filters replaced......in rougher seas 3 to 4 ft at 3400 rpm engine are fine .....above 3400 rpms even in 2 t… read more
Abiorca
Abiorca
Proprietor
Vocational, Technical or Trade Scho
1,768 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
17,310 satisfied customers
2006 Mercury 115 Hp 4 stroke engine. Will not idle. At full
2006 Mercury 115 Hp 4 stroke engine. Will not idle. At full throttle runs well no missing no smoke. At 3/4 throttle starts to miss with a 1000 rpm dip on tach, at 1/2 throtttle much worse with a 2000-… read more
Noel
Noel
Marine mechanic
Diploma
44 satisfied customers
I have a Mercury Classic Fifty (45) hp 1989 3ngine. The problem
I have a Mercury Classic Fifty (45) hp 1989 3ngine. The problem i am faced with is this. The engine had been running fine we were at high throttle when all of the sudden the engine dropped to 3000 rpm… read more
Whitecap36
Whitecap36
Service Manager/Technician
Vocational, Technical or Trade Scho
1,476 satisfied customers
I have a 2000 Mercury 50 hp outboard. It was running fine over
I have a 2000 Mercury 50 hp outboard. It was running fine over the weekend until Sunday. I was going across the lake at near full throttle when it began to bog and lose power. It would idle okay and n… read more
Jeremy R
Jeremy R
1,069 satisfied customers
I have a 150 hp marnier motor it idles good but when you give
I have a 150 hp marnier motor it idles good but when you give it gas it will spit and sputter and has no power. I have disconected O/I. what do you think.… read more
capt ron 1959
capt ron 1959
Owner/Marine Mechanic
Vocational, Technical or Trade Scho
348 satisfied customers
Took my 1983 80 hp merc to the lake today ran fine starting
Took my 1983 80 hp merc to the lake today ran fine starting off stopped to fish and when I restarted the motor seemed to miss badly would not get over hi idle and died when pushed to mid throttle. too… read more
capt ron 1959
capt ron 1959
Owner/Marine Mechanic
Vocational, Technical or Trade Scho
348 satisfied customers
I have a 20 ft pontoon boat that came with a 40 hp mercury/force.
I have a 20 ft pontoon boat that came with a 40 hp mercury/force. I swapt the motor with a 120 hp elpt mercury/force with a 21 pitch prop. Its a dog. What is the right prop?… read more
capt ron 1959
capt ron 1959
Owner/Marine Mechanic
Vocational, Technical or Trade Scho
348 satisfied customers
I have a Johnson 97 200 HP outboard that runs fine at 3000
I have a Johnson 97 200 HP outboard that runs fine at 3000 rpm, but cuts out on me at idle. I have re-built all of the carbs... changed all filters, and i replaced the fuel pump last year. I was havin… read more
davesoutboard
davesoutboard
owner
Associate Degree
1,570 satisfied customers
Outboard Motor Force/Mercury 1997 75 hp rough idle
My Force by Mercury 75 HP 3 cylinder outboard has 3 cylinders but is only running on 2. I have checked compression at 120 #s, I can ground the plug and get a great spark, and the other 2 cylinders run… read more
Captain Dave
Captain Dave
Marine Mechanic
Master's Degree
2,672 satisfied customers
hello, i would like to know what do u think about a 1997 ...
hello, i would like to know what do u think about a 1997 20 ft trophy force by mercury 120 2 stroke outboard engine. is this an outboard that is prolomatic and will be giving me lots of problem. what … read more
Pappy&#039;s Sales and Service
Pappy's Sales and Service
Vocational, Technical or Trade Scho
586 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