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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 15859
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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Loss of power. 4.3 L fuel injected searay 19.5 sport. was

Customer Question

loss of power. 4.3 L fuel injected searay 19.5 sport. was stuttering at top end like not getting quite enough fuel or air. added injector cleane and clean gas, now won't rev over 3800 and wnd slow to plane and won'teven hit 40mph (53 is normal).
Submitted: 2 years ago.
Category: Boat
Expert:  Jason replied 2 years ago.
Hello, my name is ***** ***** am I speaking with?
Who makes the engine, Volvo, OMC, Mercruiser or somebody else? Do you have a model or serial number just so I can ID it?
Next, what is the history on the engine. When was the last time it ran correctly? When did it have its last tune up? How old is the gas?
Customer: replied 2 years ago.
last year gas was running fine but stuttering at very top end like starved for fuel or air.
added injector cleaner and fresh gas, now won't give full power
Expert:  Jason replied 2 years ago.
Any idea on the last full tune up? A tune up would include cape, rotor, plugs, plug wires, and most especially.... new fuel filters.
Customer: replied 2 years ago.
previous winter, not this last season, onlyput 25 hours a season on th boat
Customer: replied 2 years ago.
stored indoors for the winter, tune up every two seasons
Expert:  Jason replied 2 years ago.
Gotcha. If there was nothing else wrong with the engine the old gas by itself would do it. Gas is good for up to 3 months after it is refined (not after you buy it). And if a fuel stabilizer is used, that can be extended to up to 6 months. (again, 6 months since refined, not when you buy it). That being said if it was last years gas it is definitely going to be no good. Being last years gas there is simply no BTU's left in it, and the octane of the gas is going to be alot lower as well, as gas looses octane naturally over time. And you would either need to pump the tanks out, or run it out and re-fill with high test. Since the gas is old after you run it out/pump it out, it would also be a good idea to change the fuel filters afterwards, does that make sense?
Customer: replied 2 years ago.
agree but it was almost empty, now super in it 70 litres, shoud have solved it, and it was running better before???
Customer: replied 2 years ago.
fuel filters something I can change easily?
Expert:  Jason replied 2 years ago.
Fuel settles out, it also attracts water. All of that "almost empty" stuff did have water in it, and that stuff is either in the tank, in the fuel/water seperating filter at the front of the engine, or both. Troubleshooting the engine is always a process of elimination. You start with the most likely common issues, and work your way down to the least common items. For example, I could say you might have a bad head gasket, start with a compression test first to rule that out. A bad head gasket is always "possible" on any marine engine. But the odds are not that high it is a head gasket, so there is no reason to start there. And that is why you start with the more common items like fresh gas and new filters. And also why I asked about a tune up. (Distributor caps do corrode from sitting, so it would still be higher on the list as "likely items") The fuel filter is easy to change, it changes like an oil filter. All Mercurys are cataloged by serial number, if you have that number handy I can get you a picture of it so you can see what it looks like.
Customer: replied 2 years ago.
would lrtting it idle for 20 minutes help clear it?
Customer: replied 2 years ago.
letting it
Expert:  Jason replied 2 years ago.
I don't understand, are you asking if it would help clear the filter?
Customer: replied 2 years ago.
clear the bad gas
Expert:  Jason replied 2 years ago.
Not really. What happens is debris, and then about 90% water, and some of the lighter fuel distillates gets trapped in the fuel filter. But a little bit of water/distalletes will still get past the filter and then off to the injectors. And to add to that, if the filter is full, it will basically overflow and overflow the bad stuff to the fuel system, does that make sense?
Customer: replied 2 years ago.
I will try it in the morning, if it doesn't, i will change the filters. thank you.
Expert:  Jason replied 2 years ago.
You are very welcome.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 start 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 youJason

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