Boat

Have Boat Questions? Ask a Boat Repair Expert.

Ask an Expert,
Get an Answer ASAP!

Boat

I have a 1989 evinrude 120 v4 and it's trying to backfire

Customer Question
out the top left carb...
I have a 1989 evinrude 120 v4 and it's trying to backfire out the top left carb if your looking at thee carbs. Replaced the cdi/powerpack and still doing it. Is this a timing issue?
JA: Sometimes things that you think will be really complicated 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 important you think the Marine Mechanic should know?
Customer: Just backfiring issue
Submitted: 1 year ago.Category: Boat
Show More
Show Less
Ask Your Own Boat Question
Answered in 2 minutes by:
7/22/2016
Marine Mechanic: Jason, Marine Mechanic replied 1 year ago
Jason
Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 16,291
Experience: Degree in Marine Technology. Gas and diesel marine mechanic.
Verified

Good morning, my name is Jason.

Popping out of the carbs is typically a lean issue. Does adjusting the idle mixture screw for that carb have any effect as to the way the engine runs?

Ask Your Own Boat Question
Marine Mechanic: Jason, Marine Mechanic replied 1 year ago

Are you still with me?

Ask Your Own Boat Question
Customer reply replied 1 year ago
Do I screw it in or out?
Marine Mechanic: Jason, Marine Mechanic replied 1 year ago

Either way, what I am curious to know is if the engines rpms change at all when you turn the screw in or out.

Ask Your Own Boat Question
Customer reply replied 1 year ago
Is there a way for me to send you a video of what is doing?
Marine Mechanic: Jason, Marine Mechanic replied 1 year ago

Sure, just upload it to youtube and copy a link over to here.

Ask Your Own Boat Question
Customer reply replied 1 year ago
https://youtu.be/AecxPFgnyK0Let me know if that works not the best on technology
Marine Mechanic: Jason, Marine Mechanic replied 1 year ago

In your video the engine was popping out of the exhaust, not out of the carb. Is it popping out of the carb as well?

Ask Your Own Boat Question
Customer reply replied 1 year ago
If it's dark you can see it between the carb and where it mounts too.
Marine Mechanic: Jason, Marine Mechanic replied 1 year ago

What is the story on this engine, have you ever personally seen it run correctly?

Ask Your Own Boat Question
Customer reply replied 1 year ago
Had it for several years. Had rebuild and ever since never ran the same.
Customer reply replied 1 year ago
Some days it runs good some days are running like crap
Customer reply replied 1 year ago
I bough a power pack/ cdi cause a few weekends ago it would cut out like something was killing power. I tested kill switch and it was good. Then only had half throttle all the way home with it cutting in and out. Sometimes just die like I pulled kill switch.
Marine Mechanic: Tan, MerCruiser Certified Technician replied 1 year ago
Tan
Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 11,093
Experience: 40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
Verified

Hello. My name is Tan.

What you have is a lean idle pop. Have you checked all the recirculation valves and hoses?

The valves are in the intake manifold and should flow in one direction only out. If any of the check valves are not working correctly this will lean out cylinders causing your condition.

Here is a diagram of the recirculation system.http://continuouswave.com/whaler/reference/graphics/OMC_V4HoseRouting.jpg

You have 4 of these valves # ***** one for each cylinder. Check each valve. Make sure they flow one way. http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1989&hp=120&model=E120TLCEM&manufacturer=Evinrude&section=Cylinder+%26amp%3B+Crankcase

Post back with questions and findings.

Ask Your Own Boat Question
Customer reply replied 1 year ago
I got 3 of the 4 out. Should there be gas in them?
Marine Mechanic: Tan, MerCruiser Certified Technician replied 1 year ago

Yes these recirculate the puddled fuel behind the reeds. The excess fuel is sucked into a different cylinder. If the valve does check it will blow air in to the wrong cylinder causing a lean fuel condition and the popping through the carb.

Ask Your Own Boat Question
Customer reply replied 1 year ago
The cylinder that is acting lean the valve is working. Did you see the video I uploaded. Sometimes the pop is random and goes away with acceleration
Customer reply replied 1 year ago
The hardest one to get to is bad. Is there anything else I need to check while I'm waiting on parts.
Marine Mechanic: Tan, MerCruiser Certified Technician replied 1 year ago

Not at this point. I have seen this condition hundreds of times and this has always been the cure. You should clean the other valves and make sure they work correctly after cleaning. I always replaced all the valves when one went bad. I had to do this as if another valve failed I had to do the labor for free. So this is something you can choose not to do if you like. The valves are pretty expensive.

Ask Your Own Boat Question
Customer reply replied 1 year ago
Thanks I got one ordered and if happens again I will replace others. It says I should get it by the 30th and will let you know what happens.
Marine Mechanic: Tan, MerCruiser Certified Technician replied 1 year ago

Ok. Please don't forget to positively rate my help as that is the only way I get credit for helping you.

Follow up questions are always welcome at no extra chage.

Thank you...........Tan

Ask Your Own Boat Question
Customer reply replied 1 year ago
Will those valves also effect wide open throttle
Marine Mechanic: Tan, MerCruiser Certified Technician replied 1 year ago

No

Ask Your Own Boat Question
Customer reply replied 1 year ago
Ok cause I ran it today and ran really good then started hearing that popping noise and didn't have enough power to get up on plane. Then kept dying when I tryed to load it
Marine Mechanic: Tan, MerCruiser Certified Technician replied 1 year ago

Ok we need to do a spark and compression test. We need to make sure we don't have another issue.

Ask Your Own Boat Question
Customer reply replied 1 year ago
Compression is the first thing I checked last time and it's 120 on all 4. I still have to buy one of the spark gap tester tools. But did use spark plug to test for spark
Marine Mechanic: Tan, MerCruiser Certified Technician replied 1 year ago

Spark plug won't tell us the strenght of the spark. If the spark is weak it won't fire under compression. That is why we have to check with a spark gap tester gapped at 7/16" to know it will fire under compression.

Try this with engine running pull each spark plug wire off at the spark plug does the engine drop rpms on all cylinders? Use insulated pliers it will shock.

Ask Your Own Boat Question
Customer reply replied 1 year ago
Is hard to tell but with it idling rough but I did notice it drop on a few cylinders
Marine Mechanic: Tan, MerCruiser Certified Technician replied 1 year ago

A few cylinders this is a 4 cylinder. That tells me it dropped on all cylinders?

Do you hear the spark arc when you remove the plug wire at each cylinder?

Ask Your Own Boat Question
Customer reply replied 1 year ago
I did not notice a sound
Marine Mechanic: Tan, MerCruiser Certified Technician replied 1 year ago

Ok we are back to using a spark gap tester. If you have one cylinder not firing it will cause your symptoms.

Ask Your Own Boat Question
Customer reply replied 1 year ago
Ok I'll try to pick one up tomorrow
Marine Mechanic: Tan, MerCruiser Certified Technician replied 1 year ago
Ask Your Own Boat Question
Customer reply replied 1 year ago
Yea I heard about them in the service manual. Been meaning to get one but kept forgetting
Marine Mechanic: Tan, MerCruiser Certified Technician replied 1 year ago

Ok keep me posted.

Ask Your Own Boat Question
Ask Tan Your Own Question
Tan
Tan
Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 11,093
11,093 Satisfied Customers
Experience: 40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.

Tan 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

691 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

16,291 satisfied customers

Degree in Marine Technology. Gas and diesel marine mechanic.

Tan

Tan

MerCruiser Certified Technician

11,093 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
Have a dragonfly 4 updated to latest now every time I turn
have a dragonfly 4 updated to latest now every time I turn it on it goes through a complete system check … read more
Matthew John
Matthew John
Cert II Electronic Engineering
40 satisfied customers
I have a 2008 Wellcraft 232 Fisherman powered with a 225 HP
I have a 2008 Wellcraft 232 Fisherman powered with a 225 HP Yamaha. Is there any reason I can't re-power with a new 300 HP Yamaha ? … read more
Jason
Jason
Marine Mechanic
16,291 satisfied customers
I own a 1965 Hatteras Motoryacht with a pair of 1965 871N
I own a 1965 Hatteras Motoryacht with a pair of 1965 871N engines. The fuel tanks are in the keel and they each have their own separate ,pick-up tubes and 1000FG racors filters, then the engine filter… read more
Boat Doc
Boat Doc
106 satisfied customers
Im getting an over heat alarm when I run on hose with muffs.
im getting an over heat alarm when I run on hose with muffs. I noticed water coming out of the peephole when the motor is not running. is that a problem?… read more
Jason
Jason
Marine Mechanic
16,291 satisfied customers
I am looking for improvements in my top end speed. I have a
I am looking for improvements in my top end speed. I have a fairly heavy bow rider. Its a 1992 Baja Islander 208 with a 350 mag. I have rebuilt the engine. It has 8.5 to 1 compression and a mild cam. … read more
MarineService8
MarineService8
34 satisfied customers
Twin 3406E 800 hp engines, under 700 original hrs Both
Twin 3406E 800 hp engines, under 700 original hrs Both produce STEAM which increases at higher rpm Clean oil analysis: no glycol..etc All gauges steady and normal Perfect performance except steam. All… read more
Cat Man
Cat Man
Vocational, Technical or Trade Scho
2,990 satisfied customers
I have a 1998 9.9 2 stroke tiller manual start mercury
I have a 1998 9.9 2 stroke tiller manual start mercury outboard. For years it gave me no problems. I pull the choke plunger out 3 times and start it right away. It runs about 30 seconds , then dies an… read more
Tan
Tan
MerCruiser Certified Technician
11,093 satisfied customers
Suzuki df 70 serging at 2800 RPMs. I have replaced the
I have replaced the Injector pump and spark plugs .plugs showed signs of too rich fuel .Tried it out started fine but serges At 2800rpms … read more
Jason
Jason
Marine Mechanic
16,291 satisfied customers
Bought a used 2001 Sea-Doo Challenger 189 Bombadier and took
Bought a used 2001 Sea-Doo Challenger 189 Bombadier and took it out today for the first time and the hull completely filled with water! Drain Plus were in … read more
Boat Doc
Boat Doc
106 satisfied customers
I have a 1985 V4 120hp outboard motor that does not want to
I have a 1985 V4 120hp johnson outboard motor that does not want to idle, the carbs have been completly cleaned and rebuilt. whole motor lubed and everything. I am getting a lean pop on idle at random… read more
Tan
Tan
MerCruiser Certified Technician
11,093 satisfied customers
Have a 997 unit. freezes up about every hr. will not shut
have a 997 unit. freezes up about every hr. will not shut off. have to diconnect power and restart. ?? … read more
Matthew John
Matthew John
Cert II Electronic Engineering
40 satisfied customers
I have a 1998 225 ocean runner that I bought. It was running
Hi, I have a 1998 johnson 225 ocean runner that I bought. It was running fine when I picked it up. It was in the back of my truck on its side for a week before I installed it. … read more
Jason
Jason
Marine Mechanic
16,291 satisfied customers
My HDS 8 lost the color palete & has horizontal black lines
My HDS 8 lost the color palete & has horizontal black lines moving from top of screen to bottom..help … read more
Matthew John
Matthew John
Cert II Electronic Engineering
40 satisfied customers
I have twin 175 hp mercurys I was told there 1989s the
i have twin 175 hp mercurys I was told there 1989s the serial #'s are ob304322 and ob304329 can't find those #'s on any list … read more
Tan
Tan
MerCruiser Certified Technician
11,093 satisfied customers
My HDS 10 will come on but not respond and keeps cycling on
my HDS 10 will come on but not respond and keeps cycling on and off? how do I fix … read more
Matthew John
Matthew John
Cert II Electronic Engineering
40 satisfied customers
I will type the summary of my problem and paste it here in a
I will type the summary of my problem and paste it here in a few minutes … read more
Tan
Tan
MerCruiser Certified Technician
11,093 satisfied customers
My 1994 evinrude 50hp tilt/trim drifts down. How do I fix
my 1994 evinrude 50hp tilt/trim drifts down. How do I fix it? … read more
Jeremy Ewell
Jeremy Ewell
Owner/Mechanic
Tohatsu Certified Technician
0 satisfied customers
I have a 50 hp 2006 merc. elpt efi outboard. that is only
i have a 50 hp 2006 merc. elpt efi outboard. that is only turning 4800- 5000 rpms and burning a lot of fuel. i have recently replaced the high pressure pump filter, plugs ,oil and filter, and foot oil… read more
Jason
Jason
Marine Mechanic
16,291 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