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Ask Dominick Your Own Question
Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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My 02 25 hp 4 stroke starts and idles great, when give it gas

Customer Question

My 02 25 hp 4 stroke starts and idles great, when give it gas it bogs down bad, doesn't die just no power and runs rough, return to idle runs smooth, what could be causing this power lose? Have cleaned carbs twice after finding bad gas, and has new plugs
Submitted: 1 year ago.
Category: Boat
Expert:  Jason replied 1 year ago.
Hell my name is ***** ***** am I speaking with? Who makes this engine, do you have a make, serial number if mercury, model number if any other brand? Who cleaned the carbs, yourself or a shop? Were they cleaned ultrasonically?
Expert:  Jason replied 1 year ago.
Are you still with me?
Customer: replied 1 year ago.
Not ultrasonic, did myself, first tone cleaning a carb
It's a Yamaha
Model F25ELHB
Customer: replied 1 year ago.
I'm Brian
Expert:  Jason replied 1 year ago.
Hi Brian, Does it bog as soon as you start accelerating, or does the engine start to build power initially before bogging down?Has compression and spark output been checked yet?
Customer: replied 1 year ago.
It builds to a pretty high idle just fine then hits a certain rpm it seems and drops out, spark and compression seemed fine when tested. Made us think ignition timing but this appears to control that by the control board.
Expert:  Jason replied 1 year ago.
Timing isn't something that changes on it's own. Have you tried running it on a different tank to rule out a tank issue, or pump the primer bulb over and over as fast as you can while a helper drives the boat?
Customer: replied 1 year ago.
Drained, cleaned and dried tank, got new fuel line and filter, ball stays primed and has no change if pumped while going, fuel pump shot fuel bout 4-5 feet so appears to being pumping strong, more sounds rich when bogs down
Expert:  Jason replied 1 year ago.
Got it. You havent' asked anything yet. So my next question is did you have any specific questions for me, or did you want me to explain how we troubleshoot these in the shop, covering all bases?
Customer: replied 1 year ago.
My question is why is it falling flat above a high idle?
Expert:  Jason replied 1 year ago.
There isn't an answer to that question other than saying the engine has a problem that needs to be found with troubleshooting. And there are a lot of steps that need to be done in order to figure out where the problem is. Would you like me to give you a call?
Customer: replied 1 year ago.
Naw I'm good, looking for Internet help. If I knew the solution myself I wouldn't of asked, so the answer is u can't help me.
Expert:  Jason replied 1 year ago.
My answer is I can explain how the engine gets troubleshot in the shop, and how to find the problem. Troubleshooting does take tools and abilities, and there are several steps to the process. But I have no idea what is wrong with your engine unless the troubleshooting gets done and I know the results.
Customer: replied 1 year ago.
I ain't paying $21 for that answer, I'm not satasfied, so u can keep ur $5 deposit but u can call ur office and tell them to refund my card asap

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