Intermittent Starting Problem of 8.1 Horizon

[rbuydens]

For the last two years, I have had a starting problem on my starboard 8.1 Horizon that occurs almost exclusively after I have been anchored for an hour or more. At the dock, the engine starts right up with no problems and rarely will there be a problem when I am underway.

However, after anchoring for awhile, the starboard engine often does not start. I can have the port engine running and use the emergency start without success. The mechanic said the emergency start was working. Sometimes, after numerous tries, it eventually will start, but recently even that wouldn't work and I had to come in under one engine. The Sea Ray Dealer mechanic I use has been trying to find the problem for two years, but when he comes on the boat, the engine starts right up. The one time when the engine didn't start while at the dock, he replaced the $2,000 computer for the engine. This winter, he replaced the plugs on both engines.

Could it be a fuel or wiring problem? Any thoughts would be appreciated.

Bob

 

[skylark]

So it doesn't turn over? Is it batteries? Simulate brig at anchor at your slip, Unplug your shore power at the dock, use the power you would use on the hook try it a couple hours later

 

[rbuydens]

Does the engine crank and crank and then not start? Or do you push the start button and nothing happens?

If it's the former, it almost sounds like vapor lock. I've never had it happen on my boat, but I've seen it in airplanes often. The only cure is to let the engine cool, and the fuel in the injection lines to turn to liquid state. The next thing is to find out why it is happening. We have a cool fuel unit on our engines, that might be a good place to start, as when it is functioning properly, it helps prevent vapor lock.

It seems like the engine is cranking. The tach shows some movement. The problem usually occurs when the engine has been off for a period of a couple of hours or more at anchor. Could the engines still be warm? Is there a cool fuel unit on a boat engine or are you referring to a plane engine?

Last year when I had the problem, I could sometimes get the engine to start by giving the engine more gas (pumping the speed control while in neutral), but that didn't work this year.

The mechanic replaced my gas hose leading to the gas tank, saying that it was worn. Could pieces from it be in the gas tank and somehow causing a problem only after bouncing around on the lake?

 

[rbuydens]

I tried the approach of being at anchor at my slip, including driving the boat for awhile and then tying up at my slip. The problem didn't occur, although it doesn't always occur (which makes it so hard to solve). The batteries seem to be fine and have been tested more than once, but in any event using the emergency start doesn't help. The emergency start button results in using the two batteries that just started the port side engine. So, it doesn't seem like a battery problem.

 

[ZZ13]

I had the exact same problem on the starboard engine of my 300DA. After all sorts of trial and error stuff I found that if I set the throttle to 1/4 throttle and left it there while cranking, it would start right up. I also found trying to pump throttle before cranking didn't do anything except make me smell gas.

 

[rbuydens]

Many thanks. I will have the mechanic check it.

Bob

 

[rbuydens]

Thanks. I will give that a try.

Bob

 

[Pair-A-Dice]

I am having a similar problem on my 8.1 starboard engine and I have measured the fuel pressure on the Schrader valve on the fuel rail. Mine was reading 35psi, and the specs I believe are 40psi +/- 2psi. That may have something to do with the issue. Are you stalling at harbor speed (lowest throttle position), or when getting on plane? Also, try opening the engine hatch to release the heat before starting and during cruising.

 

[rbuydens]

My boat normally doesn't stall once it starts. The problem is inability to start after I have been anchored for approximately one to four hours. It is not the batteries because I have cross over starting and the other engine is running when I try to start it. I used to be able to eventually get it started, but the last two times I haven't been able to do it. If I let it sit for a long time, then it starts up without a problem.

 

[rbuydens]

Didn't work. Any other suggestions?

 

[rbuydens]

After several visits and several hours by the local Sea Ray mechanic, I am still having the same problem. He replaced the crank sensor and the cam sensor and said the he tested the cool fuel module and it was fine. However, I do not believe he took it out for a sea trial when he claimed to be testing the cool fuel module. I am at a complete loss as to what to do with the problem. The Sea Ray dealer will send the mechanic out again tomorrow, but I wonder if he will ever figure it out. After he claimed that the problem was fixed last Friday, it started the first 7 times I tried and then on the next try I could get it started. I did try giving it more gas and also tried only partially pushing down on the start button a few times before pushing fully.

Any further thoughts would be most appreciated.

Thanks.

bob