I have an 09 307 with Twin Yamaha F250’s. New to me 3 summers ago. Boat has been running mint....until this Summer. What changed? I had my mechanic put a new Fusion deck with a new JL audio amp and 6 JL speakers, coincidentally I am now having some battery drain issues on Bank 1. I have two banks, with 2 batteries each. Bank 1 handles starboard engine and all electronics, Bank 2 handles port engine only and maybe the windlass. This is how Grady has it set up from factory. Long story short 5 weeks ago my bank 1 was not holding a charge and batteries were draining pretty quick, to the point where if I was drifting for a half hour with fish finder and radio on, I would not have enough juice to start STBD engine. I thought I had 4 all new (3 yr old this year) Interstate cranking batteries but it turned out that 1 of them in bank 1 was a deep cell. Never realized that last 2 years..same color green battery. Called Interstate and they told me, that is a big no, no to run different batteries in parallel and that one battery is killing the other and 2 or 3 years is about right to kill it. I put the battery switch on 1+2 fired up the STBD engine for a few minutes and I was fine for the time being. BUT moving forward I decided to move my two port starting (cranking) batteries to the STBD side. For a couple weeks, things were great....drifting for hours, STBD engine would fire up, no problem. Hang out for hours, radio cranking, fridge on etc, again no issue.....BUT just today, I did some fishing, some drifting, no issues but later on hung out by beach for about an hour with radio on, fish finder and fridge,....again engines fired up, no problem BUT while I was planing off and giving it gas, I started to trim down ....and at that precise moment right after trimming down my STBD engine started to stutter, and bog down...I put the boat in neutral and the STBD engine was running so rough, I turned it off. When I tried to restart, it would keep cranking and cranking and would not start. I went home on one engine (port) and when I got back to the dock about 30 minutes later and tried starting the STBD engine, it fired up BUT I noticed the volts were down to 12.9. When I hit trim I watched it drop to below 12. So I’m assuming that while I throttled up AND trimmed down, the volts dropped below 12....would that impact the fuel injectors to cause the engine to stall out? AND my next issue, why are my batteries draining so much in bank 1? Im 99% certain that my mechanic hooked my radio and amp up correctly. Unfortunately my Marina does not have shorepower, so I cannot hook up my battery charger. Maybe that would help if I could...I don’t know. Your thoughts? I am running 24’s as batteries but Grady specs call for 27’s...but before I replace with 4 new 27 cranking batteries I want to figure out what happened to my STBD engine today. Happy Father’s Day all!
2009 Yamaha F250 bogging down, stalled out underway
- Thread starter jlflynn1
- Start date
I wonder if you have a loose ground? Seems like a lot of electrical work and jostling stuff around. When you have a big voltage drop using the trim tilt the first place I look is to make sure all positive and negative wires are secure and tight. Then I look at the batteries. Your motor issue does seem fuel related and it very well could be what you describe .
I would start by checking all of the battery conections as that was the last thing to change. Then consider replacing the batteries, 3 years is about all I get from my bateries before I need to replace them. Check your fuel water separators for water in the fuel as the cause of then engine running rough.
Too many variables to pick a likely cause but one thing that stands out to me is that you stated that when back at the dock on one engine, you started the dead engine and it did start BUT the voltage was 12.9 and then lower. That tells me that the engine is not charging the battery.
Yes I would check cables and make sure that all of the cables are connected, especially the black (or yellow) ones that tie the batteries together. That said, the no charge issue is the first thing to look into.
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Change batteries and go from there. Definitely need use battery charger...helps keep the batteries fresh. Perhaps solar charger although I’ve never tried those. Bogging down could also be caused by clogged filters - fuel water separator, filter on engine or VST.
I’m putting 4 new DEKA 27 batteries in tomorrow. My mechanic will hopefully come out on boat for test run on Weds. I’m starting to lean toward some kind of fuel pump problem. Went out this morning and noticed both voltage meters read 14 to 14.2 volts. I thought everything was going to be fine but the minute I started to plane off the STBD engine bogged down again. I’m thinking the voltage issue is a coincidence. I’ll put that issue to bed tomorrow.
I suspect in that case that you have a clogged fuel filter or VST screen. A fuel rail pressure test will confirm if there is a loss of pressure. It wont tell you what the cause is but looking at the clear fuel filter bowl when the problem starts might help isolate, at least tell you if the issue is in the plumbing between the motor and the tank.
Also, did you try squeezing the primer to see if it was firm, soft or collapsed when the motor bogged down? Don't do these test if you are out alone.
Also, did you try squeezing the primer to see if it was firm, soft or collapsed when the motor bogged down? Don't do these test if you are out alone.
I think Seasick might have hit the nail on the head. If the fuel primers are old (3 years or so in the sun) they may have hair line cracks and sucking air in. That happened to me a couple weeks ago, changed both primers and all is well now.
UPDATE ON MY FUEL ISSUE. Turns out I had a slice in my fuel line right where it enters the engine in the harness. I figure over time with the engine tilting up or the times when the engines are not turned to the side, it pinched the fuel line enough times to split it.
Ok - thank you for the tip. I’m glad it was a simple fix. We changed the same fuel line in Port engine and it looked tired. I would imagine a lot of outboards 10+ years old have some tired fuel lines in the harness and should be addressed. Thanks again.
The best fuel line on the market is oem Omc fuel hose. It’s not cheap but worth every penny. About 8 bucks a foot for 5/16 and 3/8. I buy it by the 25 ft roll to supply my customers.