Blown Transmission??

[tn shenanigans]

Hi
I was out for a cruise yesterday, we just got up on plane running at about 3500 rmps for a minute or 2 when the port engine dropped to @ 2k rpms. I throttled back the the starboard engine and the tried to power back up however the port engine would not exceed 2000 rpms. I intially thought it was cable / linkage issue however when in neutral the engine will power up / rev up normally. We were runninng in the channel so there was no visible signs of debris / crab traps in the area that may have fouled the prop. Any thoughts on what may be going on??

Thanks

Scott

 

[dcharna]

I had a problem with my fuel system once that did the exact same thing. It might be one of two possibilities. First, I had a recall on fuel lines that actually shut down when sucked hard by the fuel pump like a straw might do. Fine under 2,000 rpm but closed tight above. Second problem I had was a screen installed just prior to my anti-siphon valve. It would get clogged and when idled down let loose. Idle back up and the foreign material would clog back up. Not sure if Sea Ray does anything to protect the anti siphon valve from getting clogged. Others can chime in. Good luck,Dan

 

[dwna1a]

What year SeaRay and which engines....I had the same issue last year with my 350 Mercs

 

[tn shenanigans]

99 380 with 7.4 mercs

thanks

 

[fwebster]

First, rule out the obvious. Get under the boat and look at the props, shafts, struts and rudder to check for an obstruction.

A "blown transmission" is usually accompanied by weird noises and overheating, so my bet is an obstruction or an engine problem that is fuel related.

 

[dwna1a]

Thunderbolt ignition system on them? Send me an email to dwna1a@aol.com I've got a service bulletin you may want to read over.

 

[northern]

Same thing appened to me twice each timeit was the fuel pump.

 

[390x]

Same thing appened to me twice each timeit was the fuel pump.

I've had this.....I've also had a bad coil do it too, but usually a coil won't rev at all. I'd really lean towards fuel pumps.

 

[dwna1a]

I sent the mail to everyone that's asked. It is for older Mercs. When mine went it would rev but only from the 900 rpms to about 1500, then it wouldn't get any better. The old thing that may help, it would only rev above 1500 if the motor was cold, once it heated up the modual would shut down. That one piece controls the timing advance past 1500 to 2000 rpms. I found a complete setup on EBay, but I don't remember the price

 

[jamesgang]

Don't know if you found your issue yet but a couple of years ago my starboard engine would intermittently drop power or shut down when going on or soon after getting on plane. Did tune-up, oil changes, etc., still acted up. In my case it turned out to be a main water pump going bad. Replaced it and no problems since.

 

[390x]

I wouldn't suspect a transmission problem at all. I'd say it's fuel or ignition, but there's not enough info to say what's wrong. Not enough fuel would make it do what you're describing, but ignition issues would do it too.

 

[Glen S]

We had the same problem a couple of years ago. Running at 3200 RPM and suddenly the port engine dropped to idle and would not throttle up. Shut it down and started up again and no sign of the problem. Had the local Mercruiser tech run a full diagnostic at the dock and at cruise speed - nothing out of spec - no fault codes. They checked the electrical connections, checked the fuel filters for water, the VST system etc and found nothing. Never been an issue since.