Clunck clack, stop.

[johnjo]

To the experienced, I'm not trying to teach granny how to suck eggs, but for others not so experienced, such as me, this may be helpful.

 

Pulling away after a pump out [don't start] clunk! the engine suddenly stopped accompanied by a clack, I had picked something up on the prop. Perhaps foolishly, I restarted the engine, kept it at tickover, engaged reverse hoping that whatever was there would unwrap & drop off, but clunk, and engine stops again. Repeated same in foreward and again a clunk and a clack and the engine stops. Moored up, weed hatch off, cut away someones lost mooring rope & carried on back to mooring, about 200 yds, no problem.

 

When I was in the engine hole messing about in the weed hatch it was obvious that the exhaust had sprung a leak as the once white paintwork was now a lighter shade of black. Removed the offending exhaust and thought whilst I had the extra space I would move the batteries off the floor and onto the swim out of harms way, something I had wanted to do for a while. Whilst doing this I noticed that the front engine antivibration mounts looked 'not quite right'. Guess what, it appears the clacks were in actual fact the front mounting bolts snapping. Took them to Uxbridge to replace the bolts, only to be told that the antivibration mounts were completely inadequate for boat engines and were more suited to workshop machinery. All my mounts base plates had '65' stamped on them which is apparently their designed weight capacity in lbs. My engine is a 3 cylinder Perkins weighing 300lbs or thereabouts so they were not really suitable to carry that in a static capacity.

 

It was then explained that even had they been 100 lbs each, they were not upto the job because boat engine antivibration mounts have to be able to sustain enormous torque [sideways twisting of the engine] especially when your prop picks up something and stops the engine dead, he also explained that the rears need to be rated higher than the fronts as they carry the extra weight of gearbox and some of the stearn gear. So I decided to change all the mounts, and off I went with 2 x 230's for the front and 2 x 410's for the rear.

 

When I was changing the rears I found that the engine supports had actually both split slightly and one had a twist. Took both to Uxbridge where they had them fixed.

 

As I was tightening down the antivibration mounts onto the bed the washers started to dish so I replaced them with some rectangular ones I made out of 3/16 steel, also because the engine supports had an elongated slot, I made some for there as well otherwise they would only have been gripping on two sides rather than all round, bit belt & braces but having got away lightly with what could have run into a huge amount of money & time I decided it not to leave anything to chance.

 

Had I been changing like for like the job would have been fairly straight foreward, but as it was there was a lot of redrilling locating holes and filing out existing ones, cutting down bolts to accomadate the alternator making washers and checking engine alignment as the job progressed I've now had the exhaust repaired and will be fitting that next week before going off to Willowbridge for a hull shotblasting and repaint. I also finished up electric wire brushing the complete engine hole and repainting it, relocating the batteries and tidying the wiring [another story] but it was all worth it.

 

So for the inexperienced, check your engine mounts are all in good condition and adequate for the job, because trying to stop a loose diesel engine banging around in the engine hole could be nigh on impossible before it has wrecked your gearbox, stearngear, tube and prop, not to mention the damage to the engine itself and the engine hole.

 

I feel so lucky I found the problem before going off to Milton Keynes!

 

Edited to add sorry it's so long, b*gger just made it longer, b*gger done it again.

Edited May 17, 2010 by johnjo