Lehman Maintenance

[Dave_E]

Hi All,

Don't get the boat for another 2 weeks, time to study. Was reading the Lehman owners manual. Couple questions for ya'll.

What is achieved by "cleaning" the lift pump every 200 hrs? It's just super filtered fuel in and out right?

Second, Do you really take all injectors out for servicing every 400 hours? What is "serviced"?

This new old boat of mine has been sitting for who knows how long in a boat house. Looks good, starts right up and ran well, sounded good to the surveyor. It's got close to 4000 hours on it. It topped out at 2200 RPM with lots of black smoke and that "You're killing me" smell. 1800 RPM purrs and no black smoke.

Thanks - Dave

 

[DavidM]

Most of those recommendations were from the days before modern fuel, oils and fuel filtering. I can't imagine what cleaning the lift pump means and injectors can easily go several thousand hours before doing anything to them.

From the numbers you indicated, your boat is over propped like most older trawlers. If you only run at 1,800 then you will be fine as you are. But if you want to run any higher I would take a couple of inches of pitch out of the prop (any prop shop can do this) to reduce load and let it get up to 2,400 or more at wot. The Lehman is rated to make its maximum hp at 2500. The black smoke should go away then.

David

 

[kchace]

Completely agree with what David said.

Ken

 

[Nordic Star]

Love your priorities! GOD/Family/Career! Have any pics? What size Lehman do you have?

 

[Dave_E]

Love your priorities! GOD/Family/Career! Have any pics? What size Lehman do you have?

Hi NS,

Thanks for the shout out. I just put a few pics on my profile album, more to come. Lehman 120, what else?

Dave

 

[CaptSteve53]

Re the Fuel lift pump: the Ford Lehman came out with a fully serviceable fuel lift pump (which most are not) there is a screen inside which can be cleaned but as you point out after coming through the inline filtration of modern times it's unlikely to get blocked and @ around $100 replacement most wouldn't bother,

Saying that when lift pumps start to fail you will notice a decrease of RPM and speed as the injection pump requires a minimum pressure to operate to specifications

An interesting fact re your RPM and HP curves is that yes Max HP is at 2500 and approx 120 Hp but your maximum torgue is at 1800 RPM at approx 240 ft/lbs

The torgue at 2500 RPM is less @ approx 225 ft/lbs (Which is normal ) Higher RPM past a certain point the torgue is reduced!

Cheers Steve