2000 Chris Craft twin Volvo 5.7l engine problem

[Stickfree]

I'm having a problem with my Port engine. I can cruise for awhile at say 2000RPM and then suddenly the Port engine goes to 0 RPMs and then after about 1 to 2 seconds goes back up to 2000 RPMs. (this can actually happen at any speed) It did this for a couple of outings, once or twice per outing. Then, when it did it again, I would have to restart the engine, as it didn't come back by itself. Did this a few times, and then finally I couldn't start the engine (wouldn't turn over). My marina mechanic said he found it water locked which he fixed and replaced the PCV valve (check valve). He thought he solved the problem, but it just happened again this weekend. Last fall they had to replace the distributor and coil on the starboard engine, but for some reason didn't do that on the Port engine. I think they should have done both and have instructed them to do so.
Anyone got any ideas as to what might be causing this?
Thanks

 

[Scott Danforth]

welcome aboard

is it the tach only that dies, or the motor?

hydro locking comes from a failing riser/manifold joint gasket, or a failing riser or manifold, or last but not least, a cracked block.

do you boat in fresh water or salt water. if in salt, when was the last time the manifolds were replaced? were OEM gaskets used, or aftermarket?

a good mechanic would have continued searching until he found the source of the problem.

 

[Stickfree]

The Tach is working ok, its the engine that quits. I boat in Fresh water. Frankly I think the cause of the problem is ignition. Last year I was having similar problems with the engine quitting and backfiring, on the Starboard side, but no hydro lock. They replaced the distributor and coil, but they didn't change the Port side. The Starboard side runs fine.

 

[CV16]

Hydro lock has nothing to do with ignition. You are getting water in the motor from somewhere. What is your compression? I'd lean towards a head gasket or cracked block.

 

[cptbill]

on my 2000 Volvo penta GSI I replace every thing two at a time, point being if it went bad on one engine it's going to go bad on the other sooner or later. Learned that lesion the hard way a while back

 

[Scott Danforth]

No way ignition has anything to do with hydro locking. Physically impossible.

Since your in fresh water, leaning toward riser gasket, cracked manifold, boat sitting low ( not enough riser height), or a bad head gasket

 

[Stickfree]

Thanks for the input everyone. And I understand that the Hydro Lock is not caused by the ignition system, but I did want it changed. Will investigate further and let you know what we find. By the way, a compression test was done after the last Hydro lock was cleared and I was told it was fine. Not sure what the compression was though.....Thanks again.

 

[cptbill]

one more thought, does your motor have the tall risers? there was a service bulletin from VP stating that you could possibly get water into the engines when slowing down quickly, It should have the 11" risers I believe( that is if it's getting water into the engine and not just shutting off)

 

[Stickfree]

Ok, here is where we stand today. We replaced both exhaust risers on the port engine, and the check valves. (not sure what size the risers were are). Was taken for a test drive and while they didn't get hydro-lock, it did splutter a few times, which I think is my ignition issue. So we are replacing distributor and coil tomorrow and doing a test drive again. Hope we have resolved this cause I just bought a new boat and will be selling this one. Easier to sell if its running well.
Thanks again.

 

[Stickfree]

Just to close this chain off, replacing the ignition has solved the problem, and both engines are running fine. Also, I sold the boat and bought a 2008 35' Rinker. Problem with the Chris Craft solved. Hope I have better luck with the Rinker.
Thanks for your help......