35 HP Chrysler slipping

[Jeff Peacock]

My wife and i have just purchased our first boat, a 15 1/2 ft fibreglas with a 35 HP Chrysler motor. The model number is 350 HA, but I'm not sure of the year (between '72 and '78). Our problem is that the motor seems to "slip" in forward gear. It starts great, runs well in idle, and well in reverse. When we put it in forward, it makes "clunking" sounds and the boat shakes slightly. This problem is magnified at higher speeds. Any ideas? Thanks! <br /><br />ps. it has nothing to do with ice on the lakes up here in Canada, so nobody get smart .

 

[jrlogan11]

Re: 35 HP Chrysler slipping

No, I think it's the ice. Yeah, gotta be...heehee<br /><br />Sounds like you have a mechanical problem in your lower unit. I'm assuming the engine isn't missing or anything, and runs fine through all of this. Another possibility, though it doesn't sound like it, is that your prop is ventilating. In other words, the engines exhaust is putting air around your prop causing it to lose it's push against the water. This is unlikely if your motor has a trim tab though, and shouldn't cause any clunking sounds.<br /><br />There is a shift clutch in the lower unit that sits between the forward and reverse gears and transfers the power to the prop shaft when you engage the gear. Sounds like this is probably slipping when you go in forward direction. I don't know how expensive it would be to fix this, and you might tear into the unit and find the problem is much worse, tough to say. You might just consider buying a replacement lower unit, if that is indeed the problem. I would have a mechanic check it first though and be sure you aren't wasting your money on my advice!

 

[eurolarva]

Re: 35 HP Chrysler slipping

My guess is the clutch dog is worn. Try replaceing lower unit oil. Run the old oil through your thumb and finger and see if there is any metal debris in the oil. If so you are grinding something in there. Before doing this put shifter in neutral and spin prop by hand in both directions. If it spins freely in both directions without a clicking noise your linkage is probably adjusted correctly. Can try this link. Sounds like similar problems.<br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=33;t=003139 <br />If you choose to reverse your clutch dogs do search under member 14290. Scotiany has done this before and I believe he has posted how to do this.<br />If you have to take the lower unit apart you will need a good manual. Without the procedures and the illustrations you will go crazy.

 

[scotiany]

Re: 35 HP Chrysler slipping

I agree with eurolarva, Drain that unit first. It's a used boat and you don't know if the LU had regular service. Reversing the clutch dog isn't that hard but , you will have to split the LU and remove the prop shaft seal housing. This would also be an excellent time to replace the impeller, drive shaft seal, shifter seal and prop shaft seal.

 

[Jeff Peacock]

Re: 35 HP Chrysler slipping

Thanks for the help...I've got a second lower unit we bought along with the boat; the guy I bought it from had a second motor of the same model, and sold us a few parts. I've changed the LU oil, and there are no metal peices in the oil. The prop spins freely in neutral, so I don't think it's the linkage. My brother and I had removed all four bolts and were going to try to replace the Lower Unit Wednesday, but decided we were out of our league! Is it imperative that I have a repair manual on-hand before changing the Lower units? That might be the dumbest question posted in a while, but the reason I ask is that I'm a pastor, and I've planned to take a couple of kids fishing tonight who've had a pretty tough week. The Lower unit, to my oh-so inexperienced eyes, looks like a fairly simple thing to change out as a whole. The only thing my brother and I couldn't figure out is where to disconnect the water intake. We had the LU hanging after removing the bolts, and I believe that everything was disconnected except the water intake. Is there any way I can change the LUs without the repair manual on-hand? Again, thanks so much for your wisdom! I'm up the creek on this one (and without a boat!). Hmm. Not funny .

 

[scotiany]

Re: 35 HP Chrysler slipping

If you have 4 hands available, installing LU ins't that hard to do. Get some antiseize compound and put it on the splines of the drive shaft. The critical thing is making sure the water pipe seats in the water pump outlet. You'll notice the linkage connector is LH-RH thread for adjusting the length. I adjusted mine just by fiddling with it until I got it right.

 

[jrlogan11]

Re: 35 HP Chrysler slipping

3 connections between motor and lower unit: driveshaft, water tube, shift rod. Driveshaft and water tube slide out on their own, shift rod must be disconnected, usually with a cotter pin as below.<br /><br />Most lower units require removal of 7 bolts, count em, 7. 3 on either side that are easy to get to, and one hidden up in the exhaust output port where the trim tab attaches. This is the port just behind the prop, not the water pee hole. You also need to remove cotter pin that holds the shift rod (front of unit, moves when you move the throttle) so that the shift rod can slide out. If you have removed all these bolts and the cotter pin, the unit should drop out. The water tube connects through a plastic fitting that will slide out on its own when the lower unit is removed. If you have removed all the bolts and the unit still won't come out, you may have a problem. If the unit hasn't been maintained with any regularity, the driveshaft splines can sometimes rust so severely into the powerhead that the driveshaft has to be cut. This is a whole new ballgame, and from what you're telling me, you may need help if this happens.

 

[Jeff Peacock]

Re: 35 HP Chrysler slipping

Thanks a bunch for the help- I missed the cotter pin and the other bolt. I think we're all good- just one more question. The guy I just talked to at the marina told us to just use 10W40 oil for the splines of the drive shaft. Is this correct? Anti-seize compound was mentioned earlier. Thanks again.

 

[nadawes]

Re: 35 HP Chrysler slipping

Hi, It is not even cold in Alberta, try move here.When you have tried all these other great ideas and they are valid try painting the portion of prop where it meets hub to see if it moves under load. These units had a weak hub. If that fails look closely at the forward gear, this model uses a gear that has the ring portion silver soldered to the dog portion and it slips under load. You probably won't be able to move it by hand, even with a big vice but again if you mark it with a punch and reassemble and try out you will then know if it moved.

 

[The Marine Doctor]

Re: 35 HP Chrysler slipping

Canuck<br /><br />I would imagine that I am not to far east of your...have done ton's of Chryslers similiar to yours...and the prop seizing on is really rare. If you have any other probs...just call us at work.<br /><br />306 933 4407<---Saskatchewan<br /><br />TMD

 

[jrlogan11]

Re: 35 HP Chrysler slipping

I have heard of people using anti-seize, but I don't think regular oil is enough. All the manuals I've read recommend a quality high pressure grease, like wheel bearing grease. I'd stick with something that can take the pressure, not just motor oil.

 

[scotiany]

Re: 35 HP Chrysler slipping

Your engine's LU has 4 mount bolts and a linkage connector with a 7/16 OE wrench compatable. It does not have 6 or 7 bolts connecting it to the rest of the LU. There is no cotter pin in your LU to worry about (unless you totally disassemble the LU). The official Chrysler(which I have) book says to use antiseize on the drive shaft splines.BTW, I think that your engine is a 1970 model made in Wisconsin.

 

[eurolarva]

Re: 35 HP Chrysler slipping

If you swap out the lower unit you might want to verify the unit you are putting in has a water impeller in the water pump. I am sure if you have never worked on lower units that all these posts can be confusing. Before installing the lower unit turn the drive shaft clockwise. You should have to put a little muscle into it. If it is kind of hard to spin chances are you have an impeller in the pump and it is working. <br /><br />When you put the lower unit back in make sure the shift linkage goes through the linkage hole. Eyeball the water pump tube to line up to where the tube connects to the water pump. If the lower unit wont go up all the way (Disconnect spark plugs for safety) turn the flywheel on the motor a little clockwise so the splines on the drive shaft line up. Put the nuts on the four bolts but only fasten them about 2 turns. This will allow you room to attach the shift linkage. The shift linkage has reverse threads on one end and forward threads on the other. I like to put the 2 inch nut (not sure what they are called) threaded all the way down on the lower linkage and then screw it up to make connection to upper linkage. Adjust linkage so that when shifter is centered on neutral you can turn prop by hand both ways with no ticking sound. Reconnect spark plugs if you disconnected them.<br />As soon as you start this motor in water look out the back and make sure water is coming out the back. If not something went wrong and you should turn motor off.<br /><br />Good luck. Hope everything goes well for you.

 

[Jeff Peacock]

Re: 35 HP Chrysler slipping

Thanks so much, fellas. BTW N. Dawes, I grew up in Ottawa, and it's much colder in Edmonton! <br />Thanks Scotiany for the info on the bolts...I spent the afternoon looking for the shift rod and the cotter pin, and the extra bolts. I was sure I hadn't missed anything, because once I took the four bolts out, the LU dropped about an inch. I can get it to there just fine, but it doesn't seem to want to move past that. Where is the linkage connector? I have a manual on the way, but I'd love to switch out these LUs this afternoon on my spare time! Eurolava, thanks for the input- very valuable. The new lower unit has some resistance, so I'm pretty sure the impeller is good to go. I'm following your directions for installing the second LU, so thanks again. The only other question I have, if anyone is still around, is if it's safe to run the motor in a 45 gallon drum after we've completed the install to ensure it's working. Sound isn't an issue, we're installing it at a buddie's farm east of town. Thanks so much for all the help, guys.

 

[scotiany]

Re: 35 HP Chrysler slipping

You're going to have to take off the motor leg covers to access the linkage connector. Sorry I didn't mention this earlier.

 

[Jeff Peacock]

Re: 35 HP Chrysler slipping

No worries- I think that was the thing I was missing. Thanks a bunch.

 

[eurolarva]

Re: 35 HP Chrysler slipping

45 gallon drum is fine as long as you dont rev it up. Keep it in neutral and keep it in idle. If you put it in forward keep your rpms as low as you can. Make sure the prop cant hit the can while it is spinning. Dont let it run to long in tank without fresh supply of water. Make sure water is coming out the back of motor. Not sure where your exit hole is. Mine is about 4 inches below the powerhead on the rear. The whole is about 1/2 inch diameter. If water is coming out at all in idle you should be okay. My chrysler does not throw much water out the back.

 

[Jeff Peacock]

Re: 35 HP Chrysler slipping

Turns out the forward gear is chipped, and needs replacing. I'm also looking for a seal kit for the gear case- on closer inspection, there was water in the oil and the reason for it was a missing prop bolt (the one that is fit for an alan wrench). Any ideas where I can get a forward gear? The others look intact, which makes sense since it only slips in forward.

 

[scotiany]

Re: 35 HP Chrysler slipping

If all else fails, what about reversing the gears and also reversing the clutch dog. Be advised though, if you change the bearings, you must also change the outer races. Bottom line-who cares if it slips in reverse. NAPA down here sells a lower unit seal kit with everything but the upper-lower gasket. You could probably make one yourself.

 

[eurolarva]

Re: 35 HP Chrysler slipping

I wasnt able to find a part for your exact model number but it looks like the 35 hp chrysler has the same part through 1978. Here is a link to the part. It is $154.76 Item 25. If you are going to buy the part from them I would email them to verify this part works on your motor. You might also want to get a new bearing cage screw. hopefully the hole for that is not stripped.<br /> http://www.mercruiserparts.com/Show.../20.png&inbr=1730&bnbr=150&bdesc=GEAR+HOUSING