1991 Mariah with 4.3L OMC cobra shifting issues

ruggles

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Hi everyone! I have been researching my issue on this board for the past 2 weeks and I have learned a lot so thank you all for your contributions. I just bought a 1991 Mariah MX19 bowrider with the 4.3L OMC Cobra setup. It has a shifting issue. When cold it shifts fine into reverse but when I shift it into forward it revs and teh gears grind for like 10 secs then it grabs. after it engages it will engage fine for the rest of day. I am not running it this way! there is no binding or anything the shifter moves very nice and freely. My question is before I drop the outdrive and order all of the tools (I will in the future anyways) are is there anything to check in on the engine side or any adjustments I can make on the boat side? Any tests at all? O bought the boat and parked it at a family members property after I bought it. It's 3 hours away so I won't be getting to it until the Christmas holidays.

Thanks for reading and Merry Christmas!!
 

bruceb58

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Mar 5, 2006
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You likely need a new lower shift cable. Hopefully you haven't wiped out the dog clutch already. Sometimes, the helm control gets sloppy as it gets older. After awhile it doesn't have enough throw to properly engage the gears.

Tilt the drive up and look at the housing where the shift cable enters the drive. that is where the cable housing usually fails causing the exact problem you are having.
 

ruggles

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Thanks Bruce. It was the previous owner that did that. I am not running it that way, hell no. So I will tilt the drive up and take a look when I get back to her next week. So there is no chance of adjustment on the engine side? I guess I'll be pulling the leg off anyways. I ordered the gasket kit and it will be in tomorrow. I don't have the special tools though so I guess I'll have to order those as well...
 

bruceb58

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When the adjustment gets that out of whack , the cable has usually failed. The problem is that if you adjust it and then it slips more, you are giving it more opportunity to ruin the dog gears.
 

ruggles

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Ok l ll order one up today. I don't want to have it all apart and just have to stare at it pissed off. Thanks for the info!
 

bruceb58

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I know its more money but I would order the OMC cable. They are more money but likely worth it in the long run.

Also, store the drive down. It will last much longer.
 

ruggles

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I had to go with a Sierra as it was the only thing I could get on short notice. $150! what a rip for a little cable. Anyways I'll be posting here as I go once I dig in next week!
 

bruceb58

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The OEM cable can be bought for $150. Sierra should be $100.
 

ruggles

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Jul 30, 2008
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That's what we deal with in Canada. We pay more for whisky made in Canada than you guys do!
 

HT32BSX115

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Dec 8, 2005
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That seems common, My daughter lives in Aukland NZ and she told me that we can buy NZ lamb cheaper here (at Costco) than they can buy it there!!
 

ruggles

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Jul 30, 2008
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picking up the seal kit and cable today. Heading to the boat on the 23rd. Can't wait to dig in. I want this boat ready for fishing in the winter and skiing in the summer. This was an ocean used boat but it''ll be going to the beautiful Sakinaw Lake in British Columbia for the rest of it's life (freshwater).
 

PARTRIDGE MAN

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May 29, 2012
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ruggles,you can get the sierra 22451 sierra cable on amazon.ca for 52 bucks Can.......and if your going to use this Boat in BC, are you going to drain the engine after every use in the winter?
 

ruggles

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Jul 30, 2008
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well that sucks! I just didn't want to wait for it to be shipped. It's a closed cooling system with coolant but I did drain the manifolds. I'll probably suck up some antifreeze through the leg once I'm done. We'll see how the repairs go. I am hoping I can make an adjustment from the boat side but I am sure I'll most likely have to pull the leg. I'll be doing it on boxing day.
 

ruggles

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Jul 30, 2008
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ok I ordered the parts from amazon and it says they'll arrive on christmas eve guaranteed. I guess we'll see but that and the seal kit on amazon saved me $140! thanks for the heads up on that one!
 

ruggles

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ok update time. I have finally put her in the water. I had adjusted the cable to where I thought I was getting both forward and reverse properly. I wanted to test it in the water though and found that makes a huge difference like I thought it would. I had reverse but when I put it into forward it would just try to die and not engage forward at all. I moved the trunnion and got it to engage forward but not reverse.

**One interesting thing is that I can manually shift it into forward and reverse though! Does that mean it's something other than the lower shift cable like the one from the helm? I will pull the leg and replace the cable if I need to. I will buy the tool first as no one seems to have it locally.

Thanks everyone!
 

Lou C

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Nov 10, 2002
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OK now something that a lot of people do not realize about the Cobra shift system its that it is TWO cables, that have to be adjusted correctly for it to shift right into both FWD and REV. First, you are adjusting the transom shift cable so it moves the bellcrank in the pivot housing equally in both directions. But think about it, what moves the transom shift cable? The bellcrank on the engine bracket which is moved by the remote control cable from the remote control. If that cable is not adjusted right, it will not have an equal throw in both gears even if the transom shift cable is set up perfect. I had this exact problem. I had perfect shifting into rev but grinding into fwd after I re-adjusted both the shift rod in the lower unit and the transom shift cable. Went back and looked at the remote control cable adjustment on the engine bellcrank and could see it had move slightly over the years. I set that according to the instructions and its been perfect.

Heres a test that will help and save you from shifting and grinding it when its not right...
Have someone shift it at the remote control, while you spin the prop, ENGINE OFF NO KEYS IN THE IGNITION. You will be able to feel, if the dog clutch fully engages both fwd and rev. If it ratchets it is still not right.

go over to the Midnight Wolf OMC tools site, he has updated adjustment instructions you can down load there that will help......
 
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ruggles

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Jul 30, 2008
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Thanks Lou. So do you think that since I can do it by hand it's probably not the lower cable but an adjustment that needs to be done on the helm cable?
 

Lou C

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Nov 10, 2002
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Well it certainly could be. I'd go back and check the transom cable first. With it disconnected from the bellcrank on the engine, have some one spin the prop and see if you can use the transom shift cable to shift the drive at the cable, to see if it goes into both gears. If so then finish adjusting it, reinstall it on the bellcrank, and then adjust the remote cable. I actually marked the cable where it goes into the sheath with a sharpie and measured how far it moved in each gear to make sure the throw was = in both.
You make one mark when its in neutral, one when its in fwd and one when its in rev. Then measure how far each of those is from the neutral position.
Other tip, when doing this the drive should be trimmed down level, so that the dog clutch can slide back and forth easily and not work against gravity. You really need a helper to spin the prop and to check that it fully engaged. It is the only way to know if the adjustments are right without running the risk of grinding it, having it jump out of gear, etc all of which will round off the edges on the fwd and rev gears as well as the dog clutch and then it will not stay in gear.
 
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