Boat

Have Boat Questions? Ask a Boat Repair Expert.

Ask an Expert,
Get an Answer ASAP!

I have an 1990 (+/-) 70 HP Evenrude outboard boat motor. If…

Customer Question
I have an 1990 (+/-)...
I have an 1990 (+/-) 70 HP Evenrude outboard boat motor. If I start it and go it runs well. If I let it warm up it will only develop 50 to 60% power.
Submitted: 3 years ago.Category: Boat
Show More
Show Less
Ask Your Own Boat Question
Answered in 1 minute by:
6/18/2015
Marine Mechanic: Jason, Marine Mechanic replied 3 years ago
Jason
Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 17,412
Experience: Degree in Marine Technology. Gas and diesel marine mechanic.
Verified
Hello my name is ***** ***** am I speaking with?
Steps 1 and 2 with any outboard troubleshooting start with checking compression with a compression gauge. And checking ignition coil output with either an adjustable gap spark testor, or a timing light. Is that something you are able to do?
Ask Your Own Boat Question
Customer reply replied 3 years ago
Compression is fine. The plugs are fine. Ignition coils have been swapped out and work fine. Timing is okay. Please refer to my original question. It runs fine unless I let it warm up.
Customer reply replied 3 years ago
This is heat related.
Marine Mechanic: Jason, Marine Mechanic replied 3 years ago
Did you check spark output once the engine was hot and the problem duplicated itself? Electrical parts can work when cold, and fail when hot, and then work when cold again.
Ask Your Own Boat Question
Customer reply replied 3 years ago
Yes all the plugs are firing when it is hot.
Marine Mechanic: Jason, Marine Mechanic replied 3 years ago
Okay, lets do another test. Take the boat back out and duplicate the problem. Then try these 2 things. 1. Pump the primer bulb over and over, will the engine pick up rpms? If no, is the bulb sucking flat or not reinflating on its own? 2. Push in on the keyswitch to activate the primer bulb. Let me know if either test yields a positive result, or no result, and we can take it from there.
Ask Your Own Boat Question
Customer reply replied 3 years ago
The bulb is fine. if I push the key in the rpms drop then recover when I let it up.
Marine Mechanic: Jason, Marine Mechanic replied 3 years ago
What were your actual compression numbers?
Ask Your Own Boat Question
Customer reply replied 3 years ago
I will have to do that test over the weekend. But why would the compression be a problem only after it warms up? that seems counter-intuitive.
Marine Mechanic: Jason, Marine Mechanic replied 3 years ago
Did you have any idea on the cutout diameter? Back in the day this boat was built there really wasn't standard sizes openings. But today there are.
Ask Your Own Boat Question
Marine Mechanic: Jason, Marine Mechanic replied 3 years ago
I don't know what happened but that last message wasn't for you.
Ask Your Own Boat Question
Marine Mechanic: Jason, Marine Mechanic replied 3 years ago
Does the alarm system work on the boat? When you turn the key to start, does it beep every time letting you know the alarm works?
Ask Your Own Boat Question
Customer reply replied 3 years ago
I checked to see if the plugs were firing when it was hot and the problem was evident. they were all firing
Marine Mechanic: Jason, Marine Mechanic replied 3 years ago
Does the alarm system work on the boat? When you turn the key to start, does it beep every time letting you know the alarm works?
Ask Your Own Boat Question
Marine Mechanic: Jason, Marine Mechanic replied 3 years ago
Good morning, it looks like you read my last reply and logged off. Did you try to send a response back, as I did not receive one.
Does the alarm work on the boat?
Ask Your Own Boat Question
Customer reply replied 2 years ago
There is no alarm. There is on issue with compression. I did experience a jolt of electricity through the steering wheel and binnacle when the motor began to loose power.
Marine Mechanic: Jason, Marine Mechanic replied 2 years ago
That sounds like either the black/yellow stop wire is chaffed, and grounding out. Or the keyswitch itself is bad and allowing voltage to leak through it. What I would do is get behind there and locate the black/yellow wire, and see if you can see if it is chaffed through anyplace. If the wire itself looks good, replace the keyswitch. Does that make sense?
Ask Your Own Boat Question
Customer reply replied 2 years ago
No, The Jolt was like from a spark plug wire. But I don't see any plug wires arching.
Marine Mechanic: Jason, Marine Mechanic replied 2 years ago
You said got a jolt through the control and the steering wheel, did I read you correctly on that?
Ask Your Own Boat Question
Customer reply replied 2 years ago
and the shifter binnacle.
Marine Mechanic: Jason, Marine Mechanic replied 2 years ago
The only wire up toward the controls that carries any voltage that you can feel is that black/yellow wire. That carries upwards of 300 volts AC, which is a bit of voltage. It is very common for key switches to fail, and cause that voltage to leak out. And then obviously if the black/yellow wire is chaffed and touching any metal that would do it as well. The way the engine works is when it is running, the stator makes that 300 volts for the ignition system, but it also sends it up a branch wire. That is the black/yellow wire. And it is called the stop wire. When you what the shut the engine off, what you do is turn the key to off, and that takes the voltage on the black/yellow and it shorts it to gorund, stopping the engine, and stopping any more voltage from being created and sent down that wire. So that is where the problem lays, either in the keyswitch or the wire itself. Does that make sense?
Ask Your Own Boat Question
Customer reply replied 2 years ago
It make sense, I will look at that.
Marine Mechanic: Jason, Marine Mechanic replied 2 years ago
You are most welcome and I would glad I could help. If you had a further question on the issue by all means feel free to ask. If not, Just incase you do not understand the way the website works (and some folks do not). You do have to put forth a positive rating in order for it to credit me for helping you. When ratings are not done, the website simply keeps your deposit and they will not credit me. The ratings box is located at the top of the screen. Please let me know if you run into any problems or errors when trying to do it or if you can not see it. If you do have a problem, just reply back "I rate Jason's service _______" and fill in the blank. Questions do not lose out, so if you have to come back tomorrow or next week with follow up questions to this you still can even after doing a rating. Thank you,Jason
Ask Your Own Boat Question
Customer reply replied 2 years ago
I will let you know what I find with the black/yellow wire.
Marine Mechanic: Jason, Marine Mechanic replied 2 years ago
Sounds good, post back if it still gives you troubles.
Ask Your Own Boat Question
Marine Mechanic: Jason, Marine Mechanic replied 2 years ago
Good afternoon. Just checking in. Did you still need help on the issue?
Ask Your Own Boat Question
Customer reply replied 2 years ago
Today is a hot day and the motor will not develop full power at all. Are there any mechanisms that will limit the motors power if it is too hot?
FYI: I found no problems with the yellow/black wire.
Marine Mechanic: Jason, Marine Mechanic replied 2 years ago
No, no mechanisms. Are you still getting shocked?
Ask Your Own Boat Question
Customer reply replied 2 years ago
Done. No compression problems. The coils are all putting out spark and the plugs have all been replaced and gapped.
Customer reply replied 2 years ago
new plug wires to.
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 Jason Your Own Question
Jason
Jason
Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 17,412
17,412 Satisfied Customers
Experience: Degree in Marine Technology. Gas and diesel marine mechanic.

Jason 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

695 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

17,412 satisfied customers

Degree in Marine Technology. Gas and diesel marine mechanic.

Tan

Tan

MerCruiser Certified Technician

11,003 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 1996 SEA-DOO GTX LOST THE KEY. CAN I BUY A REG.
I HAVE A 1996 SEA-DOO GTX LOST THE KEY. CAN I BUY A REG. LANYARD OR DO I HAVE TO PROGRAM A NEW ONE … read more
Clamp-onTech
Clamp-onTech
405 satisfied customers
Cranks but no ignition. GM 5.7 EFI 2000. Thinking ECM. It's
Cranks but no ignition. GM 5.7 EFI 2000. Thinking ECM. It's a first. Plenty of battery and starting power but nothing firing. … read more
Jason
Jason
Marine Mechanic
17,412 satisfied customers
Looking to buy a yacht with a perkins 4154 with 7000 hours.
Looking to buy a yacht with a perkins 4154 with 7000 hours. was maintained by an ex us navy marine engineer wh appeared to be meticulous judging by his records and stores. hwo should i check the condi… read more
Jason
Jason
Marine Mechanic
17,412 satisfied customers
Wont run has no ijector and sometimes no fire ,1999 mariner
wont run has no ijector and sometimes no fire ,1999 mariner 225 super mag … read more
Clamp-onTech
Clamp-onTech
405 satisfied customers
I have a 4LH-STE Yanmar Engine Impossible to get more than
Dear DominickI have a 4LH-STE Yanmar Engine Impossible to get more than 1400 RPM and black smoke Propeller clean, turbocharger replaced, injectors controled valves adjusted, fuel filters replaced . do… read more
Jason
Jason
Marine Mechanic
17,412 satisfied customers
I have a 50 hp 2000 elpto mecury outboard that I had to
I have a 50 hp 2000 elpto mecury outboard that I had to change the prop shaft seals on it serial number OG965315. I lost the spring that goes behind the dowel on the end of the shaft. I went to the de… read more
Jason
Jason
Marine Mechanic
17,412 satisfied customers
My boat is running very rough after taking it out after the
My boat is running very rough after taking it out after the winter. I think that I have water in the gas. I put in some HEET and it is running a bit better at high speed, but starts quite a bit harder… read more
Jason
Jason
Marine Mechanic
17,412 satisfied customers
I have steam coming out of my Telltale on my 89 Mariner
Hello I have steam coming out of my Telltale on my 89 Mariner Outboard. … read more
Jason
Jason
Marine Mechanic
17,412 satisfied customers
Can not get power from batter to ignition switch on a 50hp
can not get power from batter to ignition switch on a 50hp mercury 4 stroke outboard … read more
Clamp-onTech
Clamp-onTech
405 satisfied customers
I had a 1986 70 hp Mercury and I upgraded to a 1984 115 hp
I had a 1986 70 hp Mercury and I upgraded to a 1984 115 hp but forward and reverse are opposite I'm thinking the prop is the wrong rotation is there something else it could be I hooked it up the same … read more
Clamp-onTech
Clamp-onTech
405 satisfied customers
Yamaha 250 with 25hrs overheating. water pump looks new.
yamaha 250 with 25hrs overheating. water pump looks new. Could it be the thermostat? … read more
Jason
Jason
Marine Mechanic
17,412 satisfied customers
We have a 2006 Merc Optimax 150 that got some debris sucked
We have a 2006 Merc Optimax 150 that got some debris sucked into the cooling water system and slightly overheated idling while trolling. We've cleared the debris and replaced the water pump impeller. … read more
Jason
Jason
Marine Mechanic
17,412 satisfied customers
I have a Yamaha F9.9FMLH outboard, and replaced the water
I have a Yamaha F9.9FMLH outboard, and replaced the water pump recently. Now, depending on how I adjust the shift-rod coupling, I can get it to run in Forward & Neutral or Reverse & Neutral, but I can… read more
Clamp-onTech
Clamp-onTech
405 satisfied customers
I have a Yamaha T9.9EXHX 6G8X 789689. I cleaned soaked the
I cleaned soaked the carburetor but engine starts only when I cover the air mufflers , and when you remove your hand it choke and dies. Also it make sounds pak sounds and smokes a bit , it won't idle either … read more
Jason
Jason
Marine Mechanic
17,412 satisfied customers
It has been in storage for 3 years and now is cutting out
it has been in storage for 3 years and now is cutting out when I give it full throttle. I have added gas supplement. … read more
Jason
Jason
Marine Mechanic
17,412 satisfied customers
55 1978 I ran into a bed. The engine started roaring and
55 Johnson 1978 I ran into a weed bed. The engine started roaring and after weeds were cleaned off prop the engine still roared.… read more
Tan
Tan
MerCruiser Certified Technician
Certified Marine Technician
11,003 satisfied customers
I have a marine Volvo penta 5.7. This one is a tough one. It
Hello I have a marine Volvo penta 5.7. This one is a tough one. It runs great up to about 3k rpm. When you get up to closer to 4 k rpm the computer sets the rev limiter. And it looses all power. There… read more
Jason
Jason
Marine Mechanic
17,412 satisfied customers
I have an '84 E4BRHCRM (4hp with neutral)...runs well and
I have an '84 E4BRHCRM (4hp with neutral)...runs well and I'm looking to sell. Decided to replace plugs, water pump (kit 394116), and when I dropped the gear case the shaft stayed with the powerhead, … read more
Jason
Jason
Marine Mechanic
17,412 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