115hp OMC jet drive

[mohogg]

I have a 1997 northstar rougue with a 115hp omc motor and a turbo jet drive in it. I am wondering how the drive should sound when hooked to a garden hose. It sounds like the impeller is rattling and going nuts when in idle and low speeds. Is this normal or should I get a manual and start diggin around? Also it takes forever to warm up and then likes to die even after that periodically. Any clues where to start?<br /><br />Thanks guys

 

[KrisC]

Re: 115hp OMC jet drive

I have a merc jet drive, but I think the jet pumps are made by the same company. We had some loud sounds coming from it. We ended up overhauling the guts of the pump. It stopped the problem, and was fairly inexpensive with the exception of the new impeller we purchased. The reverse gate connections can also get worn out causing it to really make a racket. Make sure it is not the reverse gate before overhauling the pump. Hope my limited knowledge can help.

 

[jegervais]

Re: 115hp OMC jet drive

The noise while running on the hose is quite normal, don't worry about it.<br /><br />Regarding the warm up time, it sounds like the thermostats may have been left out (a previous overheat problem maybe?). A cold-running engine usually runs quite poorly too. <br /><br />I would start by servicing the t-stats if they're still in there, or installing new ones. Once they're installed, if the engine runs warm, then further investigation of the cooling system may be required.<br /><br />-John

 

[mohogg]

Re: 115hp OMC jet drive

Thanks for the input guys. KrisC does yours make any noise anymore when idleing or on a hose? John, T- stats you mean plural? I think I could handle that but how much noise from the bottom is too much? Should I hear it when I idle (low speeds) on the lake?If npt should I take the route of overhauling? Thanks again

 

[toni]

Re: 115hp OMC jet drive

Mohogg, I also have an omc turbo jet. Mine makes some noise at low idle too. I asked my mechanic about it and he said it was normal. Had all the bearings and seals replaced in the impellor housing and still makes noise. I take his word for it and just bump up the throttle a little, say maybe 1600-1700rpm and no noise! I've asked about a fresh water cooling kit for these engines before. I noticed that you flush yours? Where do you put the garden hose? Doesn't the "grate" need to be in water too? I think there is some seals that need water lubrication aswell. Hope this helps and hope you can help me with freshwater flushing mine. Toni

 

[jegervais]

Re: 115hp OMC jet drive

Mohogg,<br /><br />T-stats means plural. Kind of a bugger to get at on that thing too...<br /><br />Noises or "how much" noise is a very subjective thing. When running on the hose, they're noiser because you don't have a "wall of water" going thru/around the drive impeller. If it make the same amount of noise in the water as it does out of the water, then you may have a problem. If I remember correctly, a TurboJet has a much higher idle speed than the avarage outboard (around 1100 rpm), so it's common for it to be noisier. <br /><br />I don't honestly think anyone can diagnose the noise issue in a forum like this.<br /><br />Toni,<br /><br />They sell an adapter that requires loosening the drive. It fits between the drive and the transom in a cooling water passage.<br /><br />-John

 

[mohogg]

Re: 115hp OMC jet drive

OK. I got a clymer's and its usless. It doesn't have much on the turbo jet drive at all. Does anyone know how far the thrust gate needs to open when in forward and WOT? Currently it only opens up about 1/3 of the way. Should I make it open all the way to get max power? Not sure because I have never worked on one before. Also I have taken the drive off and found the source of my noise. The impeller is hitting the wall of the housing. Only in a small spot about an inch square but it is sticking enough to make it impossibble to turn by hand. I am going to tear it down and smooth that spot out so that it is not raised and see if that helps. Any suggestions or experience pointers are welcomed. Thanks guys

 

[NigelzFling]

Re: 115hp OMC jet drive

Hi, I've just rigged my reverse gate as per the OMC book i have and it works well I'll post the procedure tomorrow night for you as it's bed time here now. Nige