16'fonda with jet drive

Discussion in 'Powerboats' started by fonda73, Aug 12, 2010.

  1. fonda73
    Joined: Aug 2010
    Posts: 3
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: kent

    fonda73 New Member

    hi boat buddys,
    aquired my boat about seven years ago and over that time have pretty much restored it. i have found small snippets of info but don't know much about the history of these boats.
    mine has a 3.0 ford essex v6 connected via rubber coupling to a jet drive .
    last sunday (08/08/10) was the maiden voyage/test day through more luck than jugment it didn't sink although there was very little thrust from the jet and when i applied more power there was a fair bit of vibration that i didn't think was acceptable.
    i know that the intake is not blocked but i did notice that there is a couple of mm gap between the prop and the tube,do these tolerances have to be very tight to create the thrust ?
    if this is the problem does anybody know who deals with jetdrive repairs in s.e england (kent).

    thanks in advance guys.
    stuart
     
  2. anthony goodson
    Joined: Mar 2007
    Posts: 422
    Likes: 17, Points: 18, Legacy Rep: 256
    Location: Dorset UK & Murcia Spain

    anthony goodson Senior Member

    Before we start can you confirm that this jet is a PP 65. If you aren't sure just confirm that it is black and has a circular steering nozzle.
     
  3. fonda73
    Joined: Aug 2010
    Posts: 3
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: kent

    fonda73 New Member

    hi anthony,
    can confirm that the jet is black and it has a circular steering nozle
     
  4. anthony goodson
    Joined: Mar 2007
    Posts: 422
    Likes: 17, Points: 18, Legacy Rep: 256
    Location: Dorset UK & Murcia Spain

    anthony goodson Senior Member

    Ok 73 ,black rules out Hamilton or a Fonda GRP special,circular steering nozzle rules out Castoldi ,so you have the most common combination V6 Essex and PP65.Vibration can be caused by many things on a jet anything from a misaligned drive train to entrained air causing cavitation.Did you remove the engine during your refurbishment ? If you did check the alignment of the rubber doughnuts and their condition,whereas a UJ likes to run 4degrees or so off ,these doughnuts like to be spot dick. The symptoms you describe are not normally caused by a front bearing,so we will pass over that for now.You said the intake was clear.is there any rope around the shaft ,or damage to the impeller ,this jet combination was originally configured with a 3 bladed impeller and a five bladed stator ,check each blade through the handhole. Check as best you can that each volute in the stator is clear,by probing from the rear,sometimes a flat stone can find it's way behind the impeller and jam here. Ok so you have no blockages ,then how about air leaks causing cavitation ,there are two likely places on this jet, where the body of the jet meets the transom, and the "o" ring on the handhole cover.
    Ok still nothing yet ? then we have to dismantle the back end of the jet
    adjust the impeller clearance and check the condition of the rear bearing and polyacetal collet I have taken enough room here so I will include instructions to do this as an attachment.This is not a factory approved method just the way I do it ,I have no idea of your mechanical skills and cannot be responsible for any losses you incur neither fiscal nor fingers. Let us know how you get on PS I have typed the instructions as a Microsoft wps document ,this forum will not allow me to upload it ,if you PM me with your e-mail address I will send it to you ,unless someone on here can tell me how to convert it to a valid file it is several pages I dont want to retype it
     
  5. anthony goodson
    Joined: Mar 2007
    Posts: 422
    Likes: 17, Points: 18, Legacy Rep: 256
    Location: Dorset UK & Murcia Spain

    anthony goodson Senior Member

    OK I'll retype it bl@@dy computers
    Firstly disconnect the steering ,reverse and trim [IF FITTED] levers from the tailpipe end, and rotate the actuating levers to clear the diameter of the stator housing. Next remove the three 10mm bolts [ 17mm heads] bolts holding this assembly to the main ducting of the jet.Grasp the unit by the reverse bucket swivel points and pull the whole thing aft, it is sometimes neccessary to shake it loose, or even gently use a rubber hammer. Drain the oil from the stator bearing housing and put the unit on one side with the bearing housing facing upwards and covered with some clean rag
    You are now looking at an aluminium or aluminium bronze impeller retained on a stainless steel shaft by a polyacetal taper lock bush [collet] The rear part of the shaft will be clean, but clean the part of the shaft between the impeller and the mark left by the stator oil seal,use a plastic washing up pad or similar, this will make it easier to remove the impeller.
    Loosen the three 10mm [17mm heads] bolts holding the bush to the impeller by several turns each Now strike the outer impeller hub [the metal part wiyh the balance drillings in it] sharply forward in several places with a soft faced ,not rubber, hammer.If you don't have a soft faced hammer use a lump hammer,but protect the impeller with a soft piece of aluminium or similar. This will release the grip of the impeller hub on the plastic bush and the impeller will move forward and become loose. Do not hit it too hard or it will become stuck in the cone shaped wear ring I will point out here that this is not the factory approved method, but screwing the three bolts into the alternate threaded holes to break the taper, normally just ends up stripping the threads and or breaking the bush, which can be expensive.
    Next take an old flat bladed screwdriver and with a grinder reduce the gradient of the taper on the blade by about 50%. Tap this screwdriver gently into the slit in the plastic bush as close to the shaft as it will go,and just enough to release the grip of the bush on the shaft and key, if you have got the taper on the screwdriver right it will stay in there. I will say gently again , because if you drive it in too far you will split the bush flange on the other side. just enough to release the grip on the shaft is all you need, this is why you cleaned the shaft earlier. Now with your fingers behind the impeller blades, pull the impeller and bush complete with screwdriver ,off the shaft. Protective gloves may be useful here. The impeller blades will probably benefit from a bit of attention with a file.Do not file the leading edges sharp and do not file the circumference of the blades, just tidy it up a bit as neccessary.
    Its normally just stone chips on the leading edges that need sorting.
    Examine the plastic bush for cracks, normally found around the bolt holes and replace if neccessary.
    At this point examine the wear ring normally these are ok unless there is bad corrosion behind them which will grow and push them out of shape. Light scratching and scoring can be ignored. If you do need to replace the wear ring, first remove the plastic retaining ring and then either tap the wear ring out from the front or fold it inwards from the rear with a screwdriver and wind it out with mole grips. Try not to mangle it too much you may need it as a pattern ,in order that someone can cut and roll a new one for you.
    Push the new wear ring in followed by a new retaining ring, make sure the water inlet is in the correct place, the retaining ring should be kinked on one side towards the shaft in order to get it in, and then the kink is pushed out towards the duct wall, this is a tight fit.
    Wear ring and retaining ring can now be tapped in together with a rubber mallet. The stator should now be refitted and bolted up tight to clamp the rings in place. Remove the stator and trim off excess plastic retaining ring leaving about 0.5mm protruding, the stator uses this to clamp everything in place and help with sealing.
    The impeller tip clearances are adjusted by adding or removing shims forward of the impeller,
    So now remove the key and spacers from the shaft. Next hand tighten only the three bolts holding the impeller to the bush, the screwdriver should be removed. The bush should be a snug fit in the impeller boss, but just loose enough to push back on the shaft and turn freely. This is important as later tightening of these bolts will tend to pull the impeller aft in the wear ring taper and increase tip clearances. Push the impeller up the shaft until the blade tips just touch the wear ring. Now replace the stator assembly and refit the three bolts. With no key in the shaft you can move and turn the impeller through the hand hole cover until you find the point at which the blades are just clear of the wear ring, now measure the distance between the nose of the bush and the shoulder on the shaft, this distance determines the number of shims you need Allow a smidgen for the rearward movement of the impeller which will occur when you final tighten the impeller retaining bolts,pulling it onto the taper.
    This is fiddly and may take more than one attempt to get it right
    Fit the shims and re check
    Do not be tempted to allow the impeller to "kiss" the wear ring on this jet in the belief that it will wear itself in, this may be ok for early Hamiltons, but this is a mixed flow impeller running in a cone, it will do damage, just make the clearance as small as possible.
    Fit required number of shims, replace key, replace impeller, when you tighten the three impeller retaining bolts, hold the plastic bush forward against the shims and use the socket wrench like a screwdriver,only tighten with a wrist action, you must not try to pull the bush flange down to the lugs on the impeller, you will break it, it is a taper lock bush.
    Now for the stator assembly. First tidy up the stator blade leading edges with a file as with the impeller do not file them to a sharp edge, just tidy up the stone chips.
    The rear bearing is a DU bush made by Glacier Bearings ,it is ptfe covered and designed to run dry or lubricated by a variety of things ,in this case EP90 gear oil is used. The bearing surface should be grey in colour, if more than about 50% of the surface is a bronze colour replace the bearing. The bearing is just a press fit, but it can be difficult to get out ,although nothing like as difficult as the cutlass bearing in a Hamilton. A homemade slide-hammer type puller which fits through the bearing and locks behind the rear edge is the best bet, once you have moved it enough to grip the front edge with mole grips you have won. Press a new bearing into place ,and fit a new seal in the seal housing with the spring facing outwards towards the water, this seal keeps sand out,more than oil in, make sure the seal spring is stainless steel.
    Now half fill the centre cavity of the stator bearing housing with EP90 or similar and carefully slide the unit onto the shaft,be very careful not to turn the seal lip. If you wiggle the unit from side to side as you push it onto the shaft you will allow the trapped air to escape, failure to do this or overfilling with oil will hydraulic the seal out of it's housing.
    Finally tighten the three stator bolts and replace linkages and handhole cover.
    DU bushes and seals with stainless springs are available at most bearing stockists take your old parts with you and match them.

    Good Luck
     
  6. fonda73
    Joined: Aug 2010
    Posts: 3
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: kent

    fonda73 New Member

    anthony,
    many thanks will let you know how i get on
    ps. don't suppose you know any history about these boats.
    were they designed for sea or river use ?
     

  7. anthony goodson
    Joined: Mar 2007
    Posts: 422
    Likes: 17, Points: 18, Legacy Rep: 256
    Location: Dorset UK & Murcia Spain

    anthony goodson Senior Member

    Don't know much about the hulls ,as far as I know they were a lake and very much inshore ski boat ,they had quite a good reputation especially with the Ford V6. There were a lot of them made so I suppose that says something.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.