Hesitation question

[Obaby]

Thought maybe this knowledgeable Trojan group could help my neighbor with his 38' Cruiser problem. ( Twin 7.4 MPI Merc inboards <300 hrs )

He asked me along for his seasonal maiden voyage (as insurance).

1. Engines sound sweet throughout RPM range (w/without load)
2. No transmission or shaft noise noted.
3. Very clean boat, well maintained I'd say a 2001, low hours

I swear there's a hesitation in the ride ! ever so slight and intermittent in occurrence frequency. at first I thought it was Sea related but it occurred in all directions of travel. When I mentioned it the owner acknowledged he also thought there might be a problem.

I had them open the engine hatchs as well and saw NO engine miss or TACH fluctuation (thinking it was a fuel filter issue)

Anyhow, I couldnt see the transmissions very well but nothing sounded out of the norm.

What's your thoughts? I dont know enough about Cutlass bearings or shaft related problems...

Any advise ( or diagnostic tips ) would be appreciated...
Patrick

[ltbrett]

My first thought is an intermittent electrical problem. The symptoms you describe could be caused, for instance, by a loose wire on the ignition switch, an intermittent ground, a poorly bonded ground, or the breakdown of a wire. These things are a bear to troubleshoot. Begin with the engines on and start wiggling wires. If an engine stumbles, you've found your culprit.

Brett

[prowlersfish]

If you have no tach fluctuation I dont think you have engine or trans issue . could you be hearing and or feeling harmonics /vibation of the Engines just slighty out of sync ? just a thought

[Obaby]

Brett,

Humm, you know he did mention his guages between helms are a little off and the previous owner mentioned checking the grounds...

The Tachs are not digital, so I could be wrong...

I'll bring "De-Oxit" and my meter this weekend and let you know what I find.. ( And I have a handheld thermal imaging tool Fluke Ti25 that can detect resistive heat problems )

Thanks,
Let you know what I find...
Patrick

[ltbrett]

The problem with multimeters is that they don't flow much current through the wires you are testing. Poor grounds may read ok if they have continuity, but they may not operate properly due to an inability to pass much current. That said, you may get your meter to move if you wiggle the wires. This works best on analog meters--the digital ones are much harder to read. Just watch for the needle to bounce. I've found it easier to just wiggle wires with the engine running and listen for a stumble. Your problem, if it is electrical, will almost certainly show good continuity when nothing is moving.

Brett