Speed over ground and trim tabs

[carolmarie]

FYI I had my belt changed after 10 years, w/650 hrs; belt looked brand new. Mechanic did place sticker on top of guard indicating date and hours at change out.

[Cape Codder]

Just had timing belt done last month. roughly 800 hrs. Looked new. Engine box model, completed change in about 3 hours.
Niemiec Marine Mobile Service
New Bedford, MA

Totally professional!!
Top notch work.

[Michael @ Maine]

Great information - question though.

"One other thing that is worth noting with the Yanmar engine is not to run it at the same speed all the time - High speed engines need to be run through the rev range to maintain longevity."

I generally run at 3,200 RPM with making distance. Do I need to change the speed if I am running for an hour, two hours straight? What amount of time requires an adjustment? I have 530 hrs. on 2007 that has always been marina maintained - no issues.

Thanks,

MM

[Tree]

It may be worth increasing the rpm by 100 maybe two hundred for 15-30 mins. Also decreasing it will help overlong runs. High speed diesels can induce resonance I think it's called where the harmonics of the engine won't let it past x rpm. It's not common but does happen. Also your Yanmar manual will say in the operation of the engine to "race" the engine at the end of each day. I've not done this but I'm assuming the purpose behind this is to clear any build up of carbon particles?

I am just approaching 1700 hours and touch wood, the engine is strong, little or no smoke on start up except winter time and even then the smoke has gone in a few minutes. I also treat the fuel once a year with BG244 to reduce any internal carbon build up.

[Yearwood]

We have run our 6LP-STE at a max. rpm of 3400 for 14/15 years w/o problems. When trolling we put it in neutral and rev it up every hour to blow carbon.

As for trim tabs they are used to (1) balance port/starboard loads and/or (2) to obtain max performance at a given rpm. The latter can be determined by setting a constant course and constant rpm, lifting the tabs completely and then putting them down for 1 second and observing the gps speed, repeat at 2 seconds, etc. The max gps speed is the sweet spot for the given rpm. A purist might do the same at a 180 degree different course and average the results but I would suggest that is an attempt to measure no difference. At 3400 rpm I put the tabs down for 2 seconds and that is my sweet spot.

Osprey
Davidsonville, MD

[mjohnh]

Thanks to all for the great replies