Nasty noise, vibrations and other things,OMC

[Renken owner]

Hello guys, good to find this forum here! I'm from the Netherlands so sorry for my bad English. <br />Well, I've a Renken 1700 classic (17ft.) with OMC cobra 2.3L (Ford) and have some problems with it. <br />1)There is a very annoying sound comming from the transom. I can't exactly locate it but the sound travels trough the complete hull. It is a diesel-like rattling sound and it is intermittant except wenn you turn to the right or left, then is it a constant rattle. It is as loud or maybe louder then the engine itself.<br />2)Another strange thing happens to the steeringwheel. It shakes the whole time to the left or the right in random order. Even when I hold the steeringwheel very firmly, I can't stop is from shaking. It is as would you drive a bad car over a bad road with potholes.<br />3)And the last problem occurs at full throttle. The boat comes out of the water as normal but then it leans over to the left side. Ok, ik know that when a prop turns clockwise the boat has the intendency to turn counterclockwise but this is ridiculous how much it leans over. As would I make a turn.<br /><br />A few important details I must mention:<br />There are a set of hydrofoils on it (It wasn't me who's done that).<br />The prop isn't in a very good shape (a very odd shape though )<br />The steering has some play (don't know how much is normal).<br /><br />This is my first boat with a sterndrive so I don't have much experience with these things. I'm hoping that I'll find some people here who are thinking now: Oh, that problem sound familiar to me.. and can help me. (I do have a little video of it should my discription not be clear enough).<br /><br />Greets,<br />Frank

 

[Don S]

Re: Nasty noise, vibrations and other things,OMC

Time to pull the outdrive off the boat and check the ujoints, and gimbal bearing. Bet you have water in the bellows as well.

 

[Renken owner]

Re: Nasty noise, vibrations and other things,OMC

Thanks for the quick reply. I have heard about noises comming from the gimbal bearing but I didn't know if that was also my problem. I'll get myself a service manual and check/repair those things. <br /><br />Oh, I forgot to mention; my trim gauge also doesn't work. That sender would be in the gimbal-ring have I read somewhere. Could then also be the consequence of water leaking in, doesn't it?<br /><br />The replacement of that bearing and U-joint doesn't affect that leaning over at high-speed I bet. Could this be that the damaged prop is the reason of this leaning over?<br /><br />greets,<br />Frank

 

[Boatin Bob]

Re: Nasty noise, vibrations and other things,OMC

The trim sender itself is underwater all the time, they go bad all the time, there is 2 wires that come from it and go through the transom mount with a molded rubber grommet to seal it. When you get the boat up on plane do you use the trim on the outdrive to raise the bow up at all? If not you may want to try this next time out incase your bow is too low, this can cause bow steer and the boat may lean one way or the other very easily if the weight inside is slightly more on one side than the other.

 

[Purduebarry]

Re: Nasty noise, vibrations and other things,OMC

Is this a new problem? Do what Don suggested and then depending on the damage make sure the engine and drive are properly aligned when you put it back together. Any good shop can perform this. According to OMC the drive should be pulled anually to lubricate the gimbal and u-joints. Have you done yours latley? As for the prop, I think you know the answer, you are tearing up your lower unit with a bad prop, fix it or get a new one.

 

[Renken owner]

Re: Nasty noise, vibrations and other things,OMC

@Boatin Bob: I've played around a bit with the trim but I found that the bow was already quite high the whole time, even with full trim down. I tried to get the bow down a bit but it wouldn't. When I trimmed down the bow was getting a bit lower but raised again as soon as I was letting go of the trim button. The weight distribution in the boat was about equal and in front. I thought that the hydrofoil could be doing this (but I am not shure).<br /><br />@Purduebarry: For me this is a new boat but I reacon the problem must be present by the previous owner. So I also don't know when it has had it maintanance the last time (but I do have a feeling about that...)<br /><br />How can I see if my lower unit has taken some damage from a bad prop? I don't know how long the previous owner has driving around with a bad prop. Any suggestions about props? I've seen 3, 4 blade props 5 blade props so wich are best? I use the boat for towing skiers but mostly for cruising. A low fuel consumsion would also be preferable, fuel does cost about $6,86/gallon.

 

[Boatin Bob]

Re: Nasty noise, vibrations and other things,OMC

One of the first things I would do is change that prop, is the shaking you mentioned there all the time(during idle) or only when you put it in gear? A damaged prop usually won't be balanced anymore causing it to wobble on the prop shaft and wearing out bearings, shaft, bearing carrier etc. The hydrofoil is supposed to help you get up on plane quicker by lifting the stern which causes the bow to drop, if your bow is too high already even with the hydrofoil on then there is definitely something else wrong. What kind of speed and RPM's do you get at WOT?

 

[Renken owner]

Re: Nasty noise, vibrations and other things,OMC

The prop will be replaced. I've also checked the bellows and you where right, it has a leak, so those parts must be replaced also.<br />I've not looked at the RPM at WOT (was to busy holding the boat straight). The hydrofoil is a G2 Seamaster series II and the prop a 13¼ R17 MWC.