Oil Leak and performance issues

JoeInRaleigh

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Jul 5, 2017
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18
All,

Seeing a mix of power loss and upper rear lower unit leak where the lower unit fits to the rest of the motor. Just got this old 1974 Chrysler 105hp. I took it out on the water and experienced a severe loss of power. I could t get the boat to go faster than 10mph but the motor ran pretty faithfully for about an hour and a half on and off.

I know I have to address the plug wires, they are partially rusted and it looks like someone did some sort of splice on them. I figure I will need to check timing and sync also.

I am hoping a seal kit will address the leak problem, it's sort of between mild to severe. I'm ordering plug wires tomorrow and I plan on ordering a seal kit.

Am I on the right track? Going to check compression as well to validate before and after but just want to make sure I consider other things to check or plan to replace. I was thinking of getting a new belt also for the distributor just because the current one looks a bit brittle, I've also replaced the fuel line and bulb, the host from the tank to the gas hole will need to be replaced and sealed also.
 

jerryjerry05

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May 7, 2008
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There is a slotted screw on the lower side of the lower unit.
​Do NOT remove this, it will cause lot a of work to fix.

Remove the lower unit.
​Remove the water pump.
​Drain the oil.
A mixture of soap and water(to make bubbles)in a spray bottle.
Do a pressure test, spray the seals around the drive shaft and the shift shaft and on the prop shaft.
​A TINY,TINY bit of compressed air in the oil drain hole.
If a seal's bad?? it will make bubbles when the air is introduced.

A compression test would be the first thing before anything else.

​If 10mph is all you can get??
​The hub in the prop might be spun?

You'll have to make up the plug wires. They are NLA

​The timing: usually doesn't "jump" on an outboard so not much needed there.
Check it but don't adjust anything until your positive it's needed?
The belts available.
 

JoeInRaleigh

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Jul 5, 2017
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18
Thanks, I did order some plugs from iboats, I hope they fit :). Will be doing work this weekend and report back on status.
 

JoeInRaleigh

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Jul 5, 2017
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I got new plug wires installed and feel like it may have made a difference. It's hard to tell for sure because when I brought the boat out last time it really only showed signs of power loss when in the water and when trying to go wide open, it would quit on and off when shifting in gear also.

I changed my oil again and noticed this time the oil was still the original color but the oil leaking at the very top of the lower unit was dark/milky combined. I read that this is common and probably just unburned oil, it just seems like an odd place to leak from.

I'll check the prop and hub this weekend, compression as well, going to take a second attempt on the water also.
 

Nordin

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Jun 12, 2010
Messages
2,428
Not odd with unburned fuelmixture from the leg.

Exhaust is passing down through the leg and out through exhaust snort.

When idling it will build up a lot of unburned oil in the leg/LU.
 

JoeInRaleigh

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Jul 5, 2017
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18
Took the boat out this weekend after timing set and carbs sync'd, felt pretty proud of myself and after a few attempts to crank on the water I had a dead battery. I did check compression and all around 115psi.

I am thinking I may want to go ahead and replace the impeller. I am able to crank with really no issue when it comes to starting out of the water and when I drop the motor in it runs and quits. I read this might be because the difference in pressure required to run out of water vs in. If I'm going to take the lower unit off to check, I think it makes sense to replace, I'm wagering it needs to be. Going to hunt down a replacement impeller this week, add a second battery and make battery health check part of my departure list :).
 
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jerryjerry05

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Dying in the water? low rpm's.
Should be about 800 in gear in the water.
 

JoeInRaleigh

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I was able to get the impeller changed, the old one looked ok but the water pump housing gasket was in poor shape so I cut a new one out. Got the lower unit assembled and deciddd to stick the motor in a bucket to run. I just couldn't get her ton idle without me holding the cam down a little bit. I went back and adjusted the idle air mixture screws, double checked the timing and any adjustment to the idle screw on the throttle bar would not cut it. I feel like maybe the carbs needs to be cleaned but I'm not sure at this point. Any pointers?
 

kbh121956

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Jun 30, 2013
Messages
474
I would remove and rebuild the carbs. if you are careful you may not have to buy a kit. Did you go through the carb and timing sticky at the top of the forum?
 

JoeInRaleigh

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Sure did, I followed the instructions in the YouTube video. I think I'll try taking the carbs off and doing a carb soak. My gut tells me that there is a problem getting fuel or air into the carbs. It might explain the issue I had when going into wide open throttle.

I do have a suspicion that maybe my timing is slipping because I did have to make a second adjustment after adjusting a week ago. I am wondering if the flywheel could be slipping? I noticed there is a notch on the top where the nut is, I feel like something should be in that notch. Will stay focused on the carbs for now.
 

jerryjerry05

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There IS something in that notch.
There is a key that aligns the wheel so the timing stays constant.
​If that key sheared?? then the timing would be way off and the motor probably wouldn't start.

Read the rest of the sticky's at the top of this forum.
Lots of tips.


Try running with the cover off.

​If it's running at idle and wide open? then the carbs seem to be doing what they are supposed to.

​Take the float bowl off the top carb and see what's in there???
If you find a lot of crud?? then try cleaning.
A soak is usually needed if there is lots of hard residue in the carbs.
​I use carb cleaner spray.
​Then wash in Dawn soap and then clear water and compressed air to dry.
​Don't use WD or any sprays after drying.
​Install and run.
Set air screws at 1 1/2 turn out for initial setting.

​If you need to hold the roller then the linkage needs adjusting.

There is a filter under the front cover of the fuel pump.
​Check that.
​If there is any thing in there?? The tank needs cleaning or the hoses need replacing.
Any inline connectors? they can go bad a nd suck air.

Install a filter between the carb and the pump.
Fram G-2 G-3 G-12

​You use a built in tank or the 6 gal. carry on.
 

JoeInRaleigh

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Thanks, will pull the bowl today and see. I will take a pic of the notch, I don't think anything was there but will inspect further.

The tank is a built in, I thought about replacing with a portable just to ease my mind that the tank is clean. The previous owner said they replaced it with a used tank. I did check the fuel filter on the pump and the screen looked clean.

There was a large amount of oil in the bucket when I was running. I guess this is unburned oil?
 

jerryjerry05

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Yes probably unburned gas/oil.
IF??? the screen on the pump is clear.
Then the tank is probably clean.
​But could have water in there.

That's where a water separating filter comes in handy.
 

JoeInRaleigh

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I soaked my carbs today and set timing again, I realized last time that I did not set to WOT when doing it. The motor had a little problem starting, I pumped the gas line, sprayed some carb cleaner spray into both carbs and the motor hesitated a bit and then started like a champ.

Now the motor starts on the first try and doesn't stall. I finished around 9 tonight and am going to try again in the morning. If everything goes well I'm taking the boat back out to the lake for another try. So far I've only been out on the water riding once, the other times I fail at the dock :(. I'm also charging the batter overnight to not have the dead batter problem again.
 

JoeInRaleigh

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Started right up this morning. There is a very small stutter where the motor will kind of jerk a bit every 10-15 seconds or so. Not sure if this is a problem or not. Here is a video I took of it happening.

https://youtu.be/v8_lLcVBzV4

Something I should be worried about?
 

JoeInRaleigh

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So I kind of think I got it taken care of, adjusting the idle mixture screw clockwise smoothed it out, I tried not to let it idle too fast. Bout to head to the lake for a test drive.
 

JoeInRaleigh

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Ok, just got done on the lake and the good news is that I could leave the dock, the bad news is that I'm back to the original problem in which I can't go faster than 10mph. The boat acts like maybe it's not getting fuel.

I've done the following so far:

New plugs
Timing and sync
New plug wires
New impeller
Checked fuel screen
New squeeze ball and line from fuel tank

After about 15-25 min at 10mph the motor stalled, ran for a bit and stalled again. I thought maybe it was flooded or maybe running hot so I let it sit. After about 5 - 10 mins I tried again and could run for another 15 mins or so.

Going to do a test on the fuel lines and fuel pump. I thought maybe I need to check my points to but haven't been able to link points to this behavior yet.
 

jerryjerry05

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Check for water.
Internal tank or 6 gal??
Check for water.
​Built in tank, tilt the boat up and draw off 2-3 gal and see if water is present.

Does the ball pump up hard?
​Does it miss under load?



Run the motor and pull the plug wires off 1 at a time.
 

JoeInRaleigh

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Jul 5, 2017
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The ball is medium-ish maybe, I'm not sure honestly because I don't have anything to compare to. I had thought about getting a portable tank, the current one is built in.

It is lean sneezing a bit under load. What would I be looking for by removing spark plugs?

I've read a few posts and the problem seems to be either cd module, fuel pump or points. I'll def do a water test, I'll even replace the tank since I just don't feel good about the tank that's on the boat now.
 

jerryjerry05

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When you pump the ball it should get hard.
Then when you start, it goes soft.
It's only job it to help prime the fuel system.

​Not getting hard means the fuel pump diaphragm, or the needle valves in the carb isn't seating right.
​Pull the pump and check the diaphragm.
​Any holes or stretched, ballooned diaphragm will cause problems.

If you have good spark at idle? then the points, pack are probably ok.

​Any fuel coming from the front of the carbs?

​A sneeze could be a loose carb nuts, bad gasket on the carb or the cyl.covers.

Check the diaphragm.
​Then as it running, spray some starting fluid around the motor(not in the carbs) and see if that makes a difference in the way it runs.
 
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