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Problems changing the impellor, and recommending the Speedseal covers

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    Dear All,

    I change changed the standard raw water pump cover for a Speedseal which has made replacing the impellor much easier. Attached are the findings during the installation.

    If like me your raw water pump is hard to get to this will help,




    with attachment


    I also changed out to the Speedseal on my Yanmar 4JH4. Your description is spot on Richard and I went through the same learning process as yourself. The reason I changed out to the Speedseal is although the access to the pump is ‘Okay’ it still involves spread-eagling oneself across the top of the engine and using your head like an anglepoise lamp to see what is going on.

    The only problem I had was on start up when the the whole thing leaked very badly even after additional clean up of the pump face. I did solve the problem which, I think, although not totally sure, was due to my over greasing of the teflon and brass inserts, which, due to the thickness created, may have not allowed the face of the Speedseal to fit neatly with the face of the pump. I could have used a tool to tighten up the hand screws but that would have defeated a significant advantage of the Speedseal which is the screws need only be hand tight. After four attempts I got a good seal and that was immediately after I removed some of the clear grease.

    So far so good indeed. I have about five hours on the engine since fitting and no signs of a problem.

    David Babsky

    Thanks for the description and photos, Richard!

    I had a similar problem when changing my impeller a few years ago – also on a Ford Lehman 90hp – and when trying to change the engine fan belts. (In fact I later found that I’d snapped a tendon while twisting my left hand into position to unfasten the raw water pump’s four front screws!)

    So I cut a small access door through the bulkhead, from the saloon into the engine compartment, at about the level of the front of the engine’s alternator.

    There were several layers of metal mesh soundproofing and glass-fibre insulation to cut through: I used a teeny angle grinder to cut a square hole, then asked our local boatbuilder at Ramsgate, Steve Parish, to fit some beading to the cut-out panelling, and a fixing catch, so that the removable square panel fits back neatly into the hole, and is completely unnoticeable.

    This gives easy access to the front of the engine, is way above floor level (so doesn’t badly compromise water-tight integrity between the engine compartment and the saloon) and makes it simple to change, or adjust, belt tension and to reach the raw water pump.

    I’ve been meaning to fit a Speedseal cover, but waited for a “real-world” recommendation from someone who’s already fitted one, to see if it was worth the bother.

    You’ve now convinced me!

    (I’ll see if I can find the photos which I took for ‘Catalog’ ..I’ll post them here when I find them.)


    In your very detailed paper you write :

    Now I just need to get 2 thumb screws out and two slackened to change the impeller

    May I add one piece of advice based on pratical experience as one day or another a screw or a bolt will escape your fingers and fall into that extremely deep pit that houses the engine, so deep that human hands cannot reach the bootom watever the location of the human body. Of course a magnetic ‘finger’ will help provided the screw is made of magnetic stainless steel.

    This is why I always install a robust bag under very close to the candidate falling bolt, screw or filter or whatever is the candidate, supermarket bags made of thick platics being ideal.

    Naïla is a NC33 mkII 1978 with Ford 2712 engine.


    • This reply was modified 5 years, 4 months ago by John Crump.
    David Babsky

    Silly me: I just remembered; there is no “water-tight integrity between the engine compartment and the saloon” ..there are limber holes running the length of the boat I found near Rotterdam when the saloon floor started to lift, after a split rubber engine cooling hose raised the level of bilge water over the gear box filler cap and halfway up the engine!

    That took a lot of “margarine removal” from the gearbox, and plenty of flushing oil and meths (to remove the last drops of water), till I could refill the gearbox with PROPER oil, and change the hose, and then get under way again!


    Great write up Richard.

    I have had a Speedseal for over 10 years on my 321.
    Access to the impeller on the 3JH3 is absolutely terrible and sounds similar to your description – lying over the engine, etc .
    I have always found that removing the impeller itself is still a massive problem because it is stuck on the shaft and it is easy to damage the pump casing edge if you use a screwdriver.
    Before I ever did it I called in the Yanmar agent and watched a professional do it one handed with a screwdriver without even seeing the pump face and not lying over the engine. All by feel, amazing..
    I have never achieved that skill level.
    What I have now done is modify a pair of electrical screwdrivers (they have insulation all along the metal shaft) so the tips are bent over and sharpened so that they can maybe get behind the far end of the impeller to start pulling it out and also allow better grip by digging into the rubber.

    I also picked up a tip in a recent yachting magazine to cut a slot in the thumb screw heads so that in the event of them being so tight you can’t undo them by hand, then you can put a coin in the slot to get better leverage.

    The other thing I bought is two additional thumb screws just in case I lose one in the engine bilge. I do have a magnetic telescopic wand but the screws are stainless steel and so can’t be picked up easily with a magnet.



    we have a 2005 321. the access to the raw water pumpimpeller is indeed dreadful, made more difficult by the tiny bolts on the yan mar pump head. the speed seal cover is great. i found a jabsco small-size impeller puller tool that looks like a matching set of ‘claws’ attached to a screw mechanism. the claws insert to grab into the old impeller, and then the turning of the jabsco’s screw mechanism tightens the class and removes the impeller. to put the new impeller in, use a plastic wire tie around the outer circumference to bind the vanes smaller, so they slip easily into the chamber– and pull out the wire tie after the impeller is started into place. i am also thinking of cutting an access hole for the jabsco into the bulkhead of the battery compartment and fitting a removable waterproof plate. so the working screw end of the jabsco would be accessed by an easy reach into the battery box bulkhead then into the impeller. th small she impeller puller does fit very easily into the raw water pump body. i can only do this hole thru the bulkhead because we have replaced the huge 8 D batteries with several smaller group 31 s . so there is enough room for the impeller access panel…

    fair winds to all..

    David Babsky

    I found it very awkward to reach the fan belt and raw water pump at the front of our N33 with a Lehman 90hp motor. So I DID cut a hole through the bulkhead from the saloon (beneath part of the saloon seat) into the engine-room.

    It was tough to cut through (I used a miniature angle-grinder) as there’s a layer of steel and packing soundproofing between the two (engine compartment and saloon). I asked the local boat-builder to put a matching set of beading around the square of panelling which I’d cut through, so that when it’s back in place it perfectly matches its surroundings ..sorry, I don’t have a picture at hand to post here ..I’ll add one in the next few days.

    This makes it really easy to (a) reach the fan belts and alternator for adjustment, (b) reach beneath the motor to get to the raw water pump, (c) get to the flywheel, as I intended to add a laser-LED rev counter to our fuel-meter display.

    The teeny hatchway through from the saloon to the fan belt is a GREAT improvement, and makes access so easy! (I snapped a tendon to my little finger when trying to remove the raw water seal originally, before this easy access hatch was fitted!)

    David Babsky

    P.S: Darn! ..I didn’t realise that I’d already written this (above) in December last year! ..’Scuse the repetition, please!

    David Babsky

    Ah; here’s one of the pics – from the saloon side, beneath the seat – of the little hatch I cut through to the engine compartment..

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