Tips, Tricks and Helpful Info

Information contained on this page may be helpful. If it works in your situation great, if if does not, don't come and blame me! :-) If you think any ideas need some extra info drop an e-mail and I will add it.

If you have a tip or trick that you wish to share with others send an e-mail with all the particulars. If you wish, send photo's as well.

Priming the American turbine: Sometimes this jetunit can be a little hard to get primed. One way of overcoming this is to drill a small hole in the centre of the inspection cover and fit a hose which you take into the boat where a ball valve shutoff is mounted that can be opened when needed. This helps by allowing the air trapped in the unit to escape.

Sand trap: If you find that you have a problem with the sand trap filling up very quickly because you boat near sandy beaches or are always pumping gravel a T connector can be placed before the main sandtrap drain valve. A small valve and hose can be connected to this allow sufficient dribble to prevent a build up of sand. Note don't dump too much water or your cooling will not work.

Starting problems (electrical): Check your battery Cold Cranking Amps (CCA). Some batteries may have a good capacity but medium CCA. I found that my old battery, even though it newish did not have enough grunt to turn the motor over once hot. I change it to a marine (blue) Optima battery with 1000 CCA and it solved the problem. There are other batteries out there with the same or higher CCA but very few that weigh just 17.7kg and a high service life. With jet boats you do not need a large reserve capacity because there is only the ignition and a few auxiliaries to run.

With GM Chevrolet motors there are also different starter motors available. A high torque one is best. Generally these can be identified by a extension tube off the solenoid to where the field windings come through the case. Bigger brushes that cover more than two segments can also be fitted to give even more starting power.

Sometimes the insulating material that is used on the commutator can be too hard making the copper wear faster than the insulation between the segments. By under cutting the commutator with a hacksaw blade ( the bits between the segments) helps the brushes to make better contact.

Check the size of the lead to the starter motor, and ask your self is it big enough ? is the negative lead the same size ?

Changing the oil: One of the worst jobs to do on your boat. One way to make a big mess also.

Option One: This can by overcome by putting large rubbish bag into your bilge of the boat and emptying the old oil into it. The bag can then be easily lifted past any obstructions and into a waiting bucket for disposal at the recycle depo. Lowering the front of the boat can make the oil flow into the bag a little easier. Tip use a good thickness bag and not a supermarket one!

Option Two: Welded an elbow on to my sump which points to the transom and is in line with the bilge bung. Fit a Ball Valve on the end of the elbow along with a screw in plug. To drain the oil just put a short piece of garden hose on, and through the bung on the transom and no oil gets into the bilge. This whole system works fine. Sent in by Nigel.

Photograph sent in by Matthew (click to enlarge)

Anti seize compound: To ensure your impeller always comes off the shaft with ease use a silver type anti seize compound such as Loctite 76764. This will protect your impeller from being belted with a hammer late at night when it fails to move. Do NOT use copper or graphite base anti seize compounds.

Noise control: Having the right amount noise is great... well some might disagree. Some times the back seat or even the front seat passengers can get a bit tired of the constant rumble of the nice V8 or the scream of a twin turbo charged, intercooled quad cam Japanese. There is now on the market some light weight sound absorptive materials. These usually come in the form of a laminated construction comprising of absorptive foam with an aluminised polyester facing, and a layer of bituminous impregnated felt. These types are weigh a lot less than the old lead types of the past. If used correctly around the enclosed engine bay good results can be obtained. There are products on the market that are aluminum foil over foam, these are not designed to work as noise absorption although it may soak a small proportion up. Usually good noise control materials do cost a lot more but are well worth it.

Exhaust noise control: If you need a quick fix solution to lower the noise, then the use of some chicken mesh rolled up and forced up the exhaust pipe can make a small difference. With wet exhausts a 90 deg bend will make quite a difference.

I made a two into one system where I ran 2 90 degree elbows from water cooled manifolds into a log across the back of the motor so that the exhaust gases oppose each other and then run a single outlet from the log through the transom with water injected into it, it is very successful in reducing the noise it's almost to quiet,as I used to run 2 3inch pipes over the transom, the system I am running now is still 3inch,it is a 350 Chev motor. I did not lose any revs from changing the system. Sent in by Nigel.

Exhaust manifold cooling: If you want to use free flow type exhausts and exit through the transom one simple way of keeping them cool is to wrap them with copper tubing. Water from the heat exchanger or engine which is going to waist is put through the tubing and then inject into the exhaust after the riser. Make sure the copper is wrapped tight and there is no gap between the coils. If an extra heat barrier is needed then the use of a heat resistant exhaust wrap can be put over the top. Copper tubing used anywhere where there is vibration is subject to cracking if not secured correctly, keep this in mind.