Strange Gear Noise When Motor Quits

[Sirecks]

Hey guys. On our run out to catch some Dolphin with everyone else and their brother on Saturday, I had a set of strange occurrences with my motor and throttle.

The short story is that running along at about 5,500 RPM (30 knots or so), the motor would straight up die, accompanied with a disconnecting gear sound from the throttle quadrant. Seemed like it was popping out of gear with the motor still running, and when I pulled the throttle back to disconnect the gearing, the motor would be dead. It was the same noise that happens when you don't quite put the motor in gear and it "grinds" for a few clicks. You know what I mean? The ratcheting sound happened exactly when the motor would die. Once or twice I was able to grab the throttle and pull it back out of gear, and the motor did not quit. It did this once on the way out, about 45 miles into the run out. The motor started right back up, and ran through the whole time trolling, and all the way back past Ft. Sumter. Once in the harbor, it did this repeatedly. It would die with a ratcheting sound. After about 4 or 5 times doing this (trying to run the motor at a low RPM, mid range RPM and so forth trying to see if that would make a difference), it finally would not start back up. My son noticed that the primer bulb was completely flat at this point. I worked the bulb, and eventually got it to inflate and fill up with gas. I primed the motor back up, and it started right up and ran the rest of the way to the ramp (about 2 or 3 miles or so) without dying or giving me that ratcheting sound.

Over the past two seasons, I've had a lot of issues with the motor quitting on us that we have worked on and fixed, or so I thought. I've never had the motor die with an accompanied noise before like this. Which is why I'm so concerned about the combination.

As far as the bulb is concerned, yes, we opened the gas cap right away when we saw the bulb was flat, and let it sit for a minute or two, but the bulb stayed vacuumed shut.

Has anyone every heard of, experienced, or seen anything like this? I don't know a lot about outboards, and what I do know comes from all the work I've done on it myself using a SELOC manual and some great advice and help from those who do know. But it seems to me that if the motor is slipping out of gear, there might be a fail safe for the motor to quit if this happens uncommanded, making me think that I have a gear problem, not a motor problem, because the motor ran great all day, and started back up every time, the first time, except that last time.

Thanks for reading this, and offering whatever help you can.

 

[99yam40]

nothing is designed to shut down the motor except the kill switch and key switch.

Sounds like you have a fuel restriction and motor ran out of fuel and died.

being you did not say what motor you are dealing with we can only guess.

most outboard lower units will make a clicking noise if prop is turned when drive shaft is not turning.

the force of water running by the prop when motor shuts off with boat at higher speeds will turn the prop

 

[Sirecks]

Hey 99yam40. Sorry. My signature block has my motor. I forgot to specifically mention it. It's a 2001 250HP Yamaha OX66 Saltwater Series II. It's an SX250TURZ if I'm not mistaken.

The rush of water by the prop turning the prop makes sense. I've been trying all day to recall other instances where the motor has died in this state on me, in other words under full power. With all the various times and conditions it has given me issues over the past two years, I can't recall it just up and dying like this under full power to an instant nothing. However, the motor has bogged down, run at half power, and so forth, and then just quit in gear while running after something else (bad low pressure fuel pumps, etc.) caused the motor to run poorly. So this scenario is a new one to me I think.

Also, thanks for pointing out the only things that could kill the motor. I thought my theory might be a bit of a stretch. My only thing is twice I was running about 15 knots, with the motor about 3,000 RPM figuring if I slow rolled it in, it would keep the clicking from coming back. Even at the slower speeds, it still did it. I am guessing, though, based on what you've shared, that this is expected as well. Thanks for sharing. Now I've gotta figure out why it went from running full bore to nothing in a matter of one to two seconds, and except for that last instance started right back up strong every time.

 

[GA_Boater]

The sounds caused by the prop turning backwards with a dead motor is normal. I was hailed by the DNR for a safety check in a no wake zone shortly after launching once and just turned the key off in gear. With no motor noise the clicking is really loud and slipping into neutral stopped the racket.

You may have more than one thing going on, but the the flat bulb is pointing to a fuel delivery problem between the tank and bulb. Since opening the cap lets venting off the hook, possibly some trash in the tank is blocking the pick up, the anti-siphon valve or the hose itself. Is there a filter or water separator between the tank and bulb? And one of the valves in the bulb could be the culprit.

Do you have a portable tank you can use for testing - I'm assuming the boat tank is built in? Bypassing the main tank can help pinpoint the problem.

I'll stop at the bulb because the only knowledge I have of Yammies is limited to spelling Yamaha on a good day. The prior stuff is common and generic, not related to any brand.

Good luck, Sirecks.

 

[Sirecks]

Hey GA_Boater. The bulb is brand new. Like two months old brand new. There is also a brand new (also two month old) water filter between the tank and the bulb. I'll have to start investigating the idea of a blockage in the tank, or the tank vent outlet line.

It ran great for two hours on the rise out. It died once and then started right back up. It ran at trolling speeds for the next 5 hours and then another two hours at almost WOT on the way back. So I know that it is getting gas. If whatever obstruction is there, it became a problem at the end of the day and stayed away from the lines for over 7 hours. I can totally see that happening. I'll have to really get into my lines between the motor and the tank. Thanks for the input.

 

[Sirecks]

I guess then this leads to my next question . . . . . how does one find an obstruction, especially if it is in the gas tank? I have gently blown some air into the overboard vent tube and the pressure came right back out the vent, nice and smooth. When I prime, the first filter with the clear bowl fills with gas quickly after each pump. So I'm pretty sure I'm good between the bulb and the motor. The motor ran like a champ for so long, and then for a good amount of time after the last restart, I'm having trouble thinking it's in the motor itself. The three low pressure pumps are all brand new (like less than a year old), and I thoroughly went through the fuel system last fall chasing down other problems and cleaned out all the filters, adjusted the fuel/oil mixtures, checked all the pumps, etc. For my money, the blockage (if there is one) is in the tank at the pick up, or between the bulb and the tank. What is a good way to check these lines and areas?