Sport Jet 90 - refurbishing the pump & wear ring ?

[Keith_Olivier]

Howdy all<br /><br />I have a 94 Sea Rayder that I bought with a defective engine. I sourced a nwe engine from Almars Outboards way out in DE and the new motor runs fine.<br /><br />Loking at the trashed out motor, I found that the cooling passages were partially filled with rock debris (small pebbles and shale). I have been wondering about the performance of the jet pump, since the engine I installed seems far too willing to rev up to the maximum. The pump doesn't seem to load the engine down suficiently.<br /><br />Looking at the jet pump, I have found that the wear ring is badly scored and I would estimate the radial clearance at 40 thou (minimum). The impeller leading edge seems in reasonable shape, but it appears that rocks got between the back of the impeller and the stator and that end is chewed up. <br /><br />I have the impeller which is threaded and no amount of torque combined with penetrating oil and some heat from a blowtorch appears to be able to encourage the impeller to come free of the shaft. Is there some secret method to free the impellor that someone could share?<br /><br />Furthermore, looking at the wear ring, it appears to be an aluminum casting with some sort of paint applied. A new wear ring is between $225 (Almars) or $275 (local Mercury dealer). Has anyone had their wear ring bored out and sleeved with stainless steel or another more wear resistant material ? Any tips about how to deal with the worn impeller ? It would seem feasible to cylindrical grind the outer face of the impeller and match that diameter when sleeving the wear ring. Anybody have some exerience with this ? <br /><br />It seems a curse that Mercury built their wear rings cylindrical without any wear liner that would be less expensive to replace. Yamaha et al all have less expensive systems.<br /><br />If anyone has dealt with this before please let me know how you did it.<br /><br />Thanks Keith

 

[funpilot]

Re: Sport Jet 90 - refurbishing the pump & wear ring ?

Welcome Keith.<br /><br />The pump won't load up until it is full of water and working against the water. The rev limiter prevents over rev by cutting spark. I see about 5300 rpm in hole shot, and about 4800 rpm under load with a 120 hp sport jet. To avoid rocks in the motor, avoid running slowly in less than three feet of water. The jet pump is a powerful vacuum and will suck gravel off the bottom. At higher speed, your craft will be past the debris being sucked up by the time it reaches the surface.<br /><br />Search on JB Weld and you should come up with several posts which discuss the following repair:<br /><br />Remove wear ring and smooth JB Weld (an epoxy two part material that dries as hard as metal) into the wear ring. If your impeller is worn so it doesn't measure 6.43 inches in diameter, build up the wear ring slightly. Reinstall the wear ring until it just touches the impeller and crank the engine some. Then tighten the wear ring bolts a bit and crank the engine some more. (fuel and spark off) This will seat the wear ring (remove excess material) with the impeller and assure a very tight fit. Take it slow, don't overheat anything, and go in small adjustments. Clymers claims that performance degrades at .090 to .100 wear, but I think it starts degrading at .040 or so.<br /><br />As for your threaded impeller shaft... sorry, the 120 which I have uses an offset wrench to remove the splined impeller. However, I understand that the impeller is left hand thread and must be turned clockwise to be removed.<br /><br />Good luck,<br />fp

 

[Capt Ken]

Re: Sport Jet 90 - refurbishing the pump & wear ring ?

I've tried Marine Tex to tighten up the gap on my 90 sportjet and it didn't stay on for more than 30 minutes before it started coming off. Now it did fly during that time. Now just bought my second 120 yesterday from an old couple from Ga and it probably doesn't have 50 hours on it. 96 model and has been sitting in a barn since 98. The powder coating is still on the inside of the ring. Checked the gap and probably less than .010 where when I put a new wear ring on the 90 it was still around .030. That tells me the impeller has some wear. So this gives me one 90 and two 120s so I guess the 90 has to go this week. Starting to look like a Sea Rayder used boat lot.