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Charles
Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3342
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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99' mercury 175 efi no start : All you need

Customer Question

99' mercury 175 efi no start
JA: Thanks. Can you give me any more details about your issue?
Customer: All you need
JA: OK got it. Last thing — Marine Mechanics generally expect a deposit of about $26 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 6 months ago.
Category: Boat
Expert:  Tan replied 6 months ago.

Hello George.

Could I get the engine serial number please?

Have you checked for spark yet?

Customer: replied 6 months ago.
I'm not at the shop right now but to my recollection I think the serial number is *****
Yes I have good spark
Expert:  Tan replied 6 months ago.

Nope that isn't it.

Ok we need to check fuel pressure.

Has the engine been sitting for an extended period of time.

When you turn key on do you hear the fuel pump come on?

Customer: replied 6 months ago.
pump comes on and fuel pressure is 36psi
Expert:  Tan replied 6 months ago.

Have you checked the fuel filter for water or debris? Remove the drain plug on the bottom of the VST check for water? The engine should run with spark and fuel pressure.

Customer: replied 6 months ago.
good fuel quality and new fuel water separator. There was no water in the old separator
Expert:  Tan replied 6 months ago.

Ok I need the engine serial number to continue.

Expert:  Tan replied 6 months ago.

What size gap will the spark jump on your spark gap tester? Should jump 7/16".

Customer: replied 6 months ago.
spark is strong
Customer: replied 6 months ago.
Trigger and power packs are new
Customer: replied 6 months ago.
I have index the flywheel and check timing on in each individual cylinder as well
Expert:  Tan replied 6 months ago.

Then the only thing left is fuel getting to the cylinders. Can you squirt some fuel into the air intake while cranking will engine fire?

Customer: replied 6 months ago.
Originally the boat came in because the customer ran it extremely hot melting the impeller and housing replace impeller and housing
Customer: replied 6 months ago.
How to remove the cylinder heads and the exhaust manifold in order to remove all of the pieces of impeller that were in the cooling system. Also replace both thermostats compression is equal and good on all cylinders
Expert:  Tan replied 6 months ago.

Ok What are the compression numbers? If I have the correct engine these cylinder heads have rubber o-rings # ***** and rubber seals # ***** It is possible all the rubber has melted and you have no compression. http://www.marineengine.com/parts/mercury_marine_parts/static/img/COMMON/30726.gif

Customer: replied 6 months ago.
0g842267
Expert:  Tan replied 6 months ago.

Can you shoot squirt fuel into the air intake and see if engine will fire off?

Do you show any signs of fuel on the spark plugs?

Customer: replied 6 months ago.
If I spray with ether it will fire up. I removed the intake plenum and can see the injectors squirting fuel when cranking
Expert:  Tan replied 6 months ago.

The engine should run with fuel spark and compression. What are your compression numbers?

Customer: replied 6 months ago.
If I remember right I think it was 125
Expert:  Tan replied 6 months ago.

Hmm. This engine should run. If it runs on starting fluid I don't understand why it won't run on injected fuel? Are you getting fuel to all the cylinders?

Customer: replied 6 months ago.
It's baffling me too
Expert:  Tan replied 6 months ago.

I'm out of ideas. I will opt out maybe another expert can jump in a help.

Sorry.

Customer: replied 6 months ago.
Thanks anyway
Expert:  Charles replied 6 months ago.

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

It sounds like you are a tech as well, is this true?

Customer: replied 6 months ago.
Expert:  Charles replied 6 months ago.

Does you scan tool show any faults?

did you also check the tuner when you had the gear case off?

Customer: replied 6 months ago.
Tuner?
I am using a Sierra stats. I am only able to read live data, status monitors, and ECU identity
Expert:  Charles replied 6 months ago.

the tuner, or exhaust extension, located inside the driveshaft housing to carry the exhaust away from the powerhead. When these engines get hot, they have a tendency to get loose of fall off.

Customer: replied 6 months ago.
I'm not sure I know what you're talking about. Could you send a diagram
Customer: replied 6 months ago.
It does not appear that that has fallen off in any way. However I did find that the gasket between the power head and the adapter plate is blown out around the exhaust ports
Customer: replied 6 months ago.
I am currently in process of replacing that gasket
Expert:  Charles replied 6 months ago.

If you have the gear case off, just reach into the exhaust chamber from the bottom. You can then feel the tuner and try to wiggle it.

Customer: replied 6 months ago.
What are your thoughts on that gasket being blown out around the exhaust? Do you think that could cause a no start?
Expert:  Charles replied 6 months ago.

Not really a no start, unless it was blocking the ports or allowing water to be drawn into the cylinders.

Customer: replied 6 months ago.
What effect would the exhaust tuner falling loose have on the engine
Expert:  Charles replied 6 months ago.

Not being able to carry the exhaust away from the powerhead and into the water level inside the housing. Basically it would choke the engine.

Customer: replied 6 months ago.
I will check into it and get back to you
Expert:  Charles replied 6 months ago.

Great.

Customer: replied 6 months ago.
I have the drive unit removed. Everything seems to be okay. Nothing is loose as far as I can tell
Expert:  Charles replied 6 months ago.

It is was loose, you would be able to wiggle it from the bottom.

How is the powerhead gasket replacement going?

Customer: replied 6 months ago.
Complete. I haven't attempted to start the engine yet. I wanted to see about the tuner first
Expert:  Charles replied 6 months ago.

I saw the the grommet from the water pump was stuck on the water tube, Make sure that you remove it from there and install it back into the pump housing first.

Customer: replied 6 months ago.
Of course... I'll reinstall the drive and see what happens
Expert:  Charles replied 6 months ago.

It would be really odd to be that gasket, but I guess anything is possible.

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