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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 16093
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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, I got a 99 mercury 150hp blue water series,

Customer Question

Customer: luis.
JA: Thanks. Can you give me any more details about your issue?
Customer: I got a 99 mercury 150hp blue water series, giving me problems cranking while on the water which may be at cold start
JA: OK got it. Last thing – JustAnswer charges a fee (generally around $26) to post your type of question to Boat Experts (you only pay if satisfied). There are a couple customers ahead of you. We can help you for less if you're not in a rush. Are you willing to wait a bit?
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Submitted: 1 year ago.
Category: Boat
Expert:  Jason replied 1 year ago.

Hi Luis, my name is ***** ***** I will be helping you today. I don't quite understand your question. What kind of issues are you having and how can I be of help to you?

Also, all Mercurys are cataloged by serial number, do you happen to have that number handy?

Customer: replied 1 year ago.
i can crank my motor on a garden hose at the second or third try with no much trouble, when i get to the ramp it cranks with ease, i usually anchor for about an hour or so and move on to two or more destinations and do the the same. when i try to crank the motor it has a hard time staying on, it takes me a good while to get it on, when i finally get it warm it usually performs just fine until the next stop. now i usually press on the bulb, turn key to on position, press down choke for a few seconds as i'm turning the key, when cranked i bring the throttle only lever forward about a 1/3 to warm up..
after the motor is on it idles just fine.
maybe i'm not using the right cold start procedure?
What do you think?
Expert:  Jason replied 1 year ago.

Got it. The engine is either vapor locking or it needs to be reprimed in between stops. When it is hard to start, are you pumping the primer bulb until firm in order to re-prime it first?

Customer: replied 1 year ago.
Expert:  Jason replied 1 year ago.

Got it. Another question for you. On your carbs. Any idea on the last time they have been rebuilt and tuned?

Customer: replied 1 year ago.
the previous owner told me they were rebuilt 2 years ago
Customer: replied 1 year ago.
do you know what the correct cold start procedure is for this motor?
Expert:  Jason replied 1 year ago.

On a true cold start you would pump the primer bulb until firm, turn the key to run. Push in on the key anywhere from 5 to 10 seconds in order to prime it. And then turn the key to start. That is the correct way to start it when cold.

When hot, this is a carbureted engine and not fuel injected so there are a lot of variables. Sometimes you can just turn the key. Other times you have to pump the bulb again. Other times you have to do both and then push in on the key again. Fuel injected engines are turn key, every time, hot or cold, just turn the key and it starts. Cold engines have to be primed. If they are flooded you have to open up the throttle. If not flooded you have to keep the throttle closed. And then of course carb'd engines can vapor lock, where that does not happen to fuel injected engine. Are you familiar with what vapor lock is?

Customer: replied 1 year ago.
no, what is vapor lock?
also, when they are flooded you have to open the throttle?
i'm i suppose to have the throttle (warming only) lever forward 1/3 while pressing on the choke (priming) then turn the the key to start ?
Expert:  Jason replied 1 year ago.

when they are flooded you have to open the throttle?

If it is flooded, opening the throttle would help clear the flood, and allow it to start easier. But if they are not flooded, opening the throttle would make it harder to start.

i'm i suppose to have the throttle (warming only) lever forward 1/3 while pressing on the choke (priming) then turn the the key to start ?

Only when starting the engine when it is completely cold. Such as the first time in a day.

no, what is vapor lock?

Vapor lock is what happens when fuel is left to sit resting on a hot engine. Think of the engine compartment as an oven. And the fuel in the carburetors fuel bowls as a pot of fuel sitting in that oven. What happens is eventually it begins to boil, and turns into vapor.

Watch this 3 part video, it does a good job of explaining it as well. Click these links below

Now if you are getting vapor lock there are 3 distinct things to do that will help.

1. Run non-ethanol fuel if you have it available in your area. Ethanol free fuel has a much higher boiling point.

2. Make sure the cooling system on the engine is serviced, and that the engine is not running any hotter than it needs to be.

3. Before you shut the engine off, let it idle for a minute or 2 first. This will help the engine cool down.

I think that should do it. But I work for tips so I do want to make sure you are happy with my service before you go. If you had a further question on the issue by all means feel free to ask. If not, Just in case 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. To rate, you must select the star you wish and also confirm it. Please let me know if you run into any problems or errors when trying to do it. If you do have a problem, or if you can not see the ratings box which is at the top of the screen. Please reply back "I rate Jason's service _______" and fill in the blank.

Questions do not close out, so if you have to come back later on with follow up questions to the issue you still can even after doing a rating.

Thank you

Expert:  Jason replied 1 year ago.

Hello, I noticed no rating has been put through. The website has charged you but they will not credit me for helping you out until that rating is complete. Did you have any further questions on the issue?