What’s slow­ing my Lis­ter down?

Canal Boat - - Back Cabin: -

QMy Lis­ter ST2 starts fine, but over the course of an hour the boat’s speed will drop from 4mph down to 1mph. In­creas­ing the throttle just over­heats the en­gine. The prop is clear. I changed the en­gine oil and put fresh ATF in the LH150 hydraulic gear­box. The prop seems to pulse out power. The en­gine seems fine. Is some­thing wrong with gear­box or pro­peller?

STEVE MACK, via email

ATONY REPLIES... Firstly, leaves around the prop are very com­mon in the au­tumn (and you won’t see them through the weed­hatch be­cause they drop away when you go into neu­tral): pop it into re­verse for a mo­ment so the leaves spin away from the prop. If not, here are some things to check.

If you have an LH150 gear­box, ATF oil is far too thin; you might have worn the clutch and brake band. It should have SAE 80 gear oil. You might also have an oval re­duc­tion box bolted to the back of the gear­box, with a sep­a­rate oil filler and drain, which again uses SAE 80.

The LH150 only uses oil pres­sure for astern and neu­tral, but the ATF in the gear­box and pos­si­bly no oil in the re­duc­tion box could be caus­ing one or other to seize up. An oil change just might solve it.

It could be par­tial en­gine seizure. Oil di­lu­tion from in­ter­nal fuel leaks is one pos­si­ble cause, but chang­ing the oil has ruled that out. It can also be caused by a re­stric­tion of cool­ing air­flow. Make sure the fly­wheel cover band with the air holes in it is free of dirt; you have cleared the cylin­der fins of any build up of dirt; the cool air in­let into the en­gine bay is large enough; and the hot air out­lets are prop­erly trunked and of the cor­rect size.

Does the stern gland get more than slightly warm? If so, it might be seiz­ing up on the shaft. The gland might be over-tight, or the en­gine and shaft might be out of align­ment.

Fi­nally, it could be a fuel prob­lem. Make sure the tank breather is clear, and try run­ning with­out the fuel filler on as a test. Change and in­spect the fuel fil­ters and strainer in the lift­pump: if you find wa­ter and dirty slimy stuff, the tank might need clean­ing.

Gear­box and re­duc­tion box fillers

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.