165 Mercruiser Leaking and no Forward

[165mercruiser]

Hi?.

I bought and in the process of restoring a 1974 20 foot boat and trailer with a Mercruiser 4 cylinder 165 I/O. I have gutted the entire boat and removed the floor. I decided to put it in the water to make sure there were no leaks. I encountered 2 problems. The first there is water coming into the boat from the bottom of the motor against the back wall. The water appears to be coming in only when the engine is running. Second I have reverse and neutral but no forward.

I am worried about the leak. Can someone enlighten me as to what to look for and what it could be? Thank you.

 

[Bondo]

Re: 165 Mercruiser Leaking and no Forward

Can someone enlighten me as to what to look for and what it could be?

Ayuh,... It Could be a rotten transom...
It Could be a bad hose,...
The only way to know is to LOOK...

The lack of shifting, Could be a Bad lower cable, or somebody reassembled the drive improperly...








edit; benchmark, 35,000 posts

 

[Ancloter]

Re: 165 Mercruiser Leaking and no Forward

Might that be a 6-cyl 165?

The water leak sounds like it's in the exhaust manifold or coupling. No biggie. Just tighten the components from the elbow riser (upside down U at the back of the block) to the outdrive.

For the shift issue disconnect the cable at the engine and move the shift lever to see if the gear engages. It can be done out of the water. If it engages using the engine connector it is a shift cable adjustment issue. If it does not shift then it's a gearbox issue. The former is fixed by rotating the cable lock-point (plastic or brass barrel-like thing) to the direction of the FWD, like 2 turns at a time until all gears are achieved from shifting at the control box. If it's the gearbox take it to a mechanic. But that is rarer occurance than a cable adjustment issue.

 

[165mercruiser]

Re: 165 Mercruiser Leaking and no Forward

It is a 4 cylinder. I will attempt the suggestions made. As for the water it is only coming in when the engine is running. Since I removed the floor I can see that the water is coming in just below the engine part which is attached to the back transom. I will let you know what I come up with. Thanks

 

[Ancloter]

Re: 165 Mercruiser Leaking and no Forward

"It can be done out of the water."

Should read it can be done out of the water, without running the engine. Just shift the gear box and spin the prop to see if it engages the gear.

Good luck.

 

[165mercruiser]

Re: 165 Mercruiser Leaking and no Forward

Here is a picture of the engine....

 

[165mercruiser]

Re: 165 Mercruiser Leaking and no Forward

Is it ok to run the engine with a pail of water like this....

 

[165mercruiser]

Re: 165 Mercruiser Leaking and no Forward

Under the engine next to the bolt is where the water comes in. When I run it with the pail there is no water that comes in. When the bost is in the water and running then water comes in like a hose

 

[Ancloter]

Re: 165 Mercruiser Leaking and no Forward

If you run it with a pail you will have a very limited amount of water and will have to shut it off after a few seconds to prevent damage to the water pump impeller and engine overheating. You may have to spend the $10 to get the muffs to run it on a hose. They're common and are sold at Wal-Mart, etc. in the boating section.

Water coming in around the transom is typical of the bellows (large, black rubber accordian-looking thing) leaking. Either the (large) hose clamp around it is lose or it has cracks in it. You can tighten the hose clamp but if the bellows is leaking it needs to be replaced.

I ran a Mercruiser with a leaking bellows and just let the bilge pump handle the leak since the boat was trailered when not in use.

If you've fixed the forward issue you've got a usable boat so long as you trailer it and have a bilge pump. Beyond that the bellows probably has to be replaced.

 

[Fordiesel69]

Re: 165 Mercruiser Leaking and no Forward

I ran a Mercruiser with a leaking bellows and just let the bilge pump handle the leak since the boat was trailered when not in use.

If you've fixed the forward issue you've got a usable boat so long as you trailer it and have a bilge pump. Beyond that the bellows probably has to be replaced.

Water coming in the boat by faulty bellows is not something to let go. The u-joints, gimbal bearing, yoke seal, etc will be very short lived. For a test run fine, but not to use for the season with blown bellows.

 

[Ancloter]

Re: 165 Mercruiser Leaking and no Forward

Ok, taking a close look at the third photo if you have water coming in around the edges of teh engine bracket you have a rotted transom allowing external water to come through. You could try loosening the bolts and prying a screwdriver back there to check if it's soft.

If the transom is leaking through try caulking it from the outside, around the bracket where it mates to the transom. If that doesn't do it either the transom or the boat has to be replaced. I paid about 3 grand to replace a transom on my fishing boat a few years ago. The boatyard thought I was crazy to save an old cuddy but it has sentimental value.

 

[Ancloter]

Re: 165 Mercruiser Leaking and no Forward

The u-joints, gimbal bearing, yoke seal, etc will be very short lived. For a test run fine, but not to use for the season with blown bellows.

Yeah, well it was an inexpensive fixer upper and I was on leave from the Army on limited time and the boat was trailered. I put it into a boat yard shop for winterization before departing. After the boat yard let it sit through a 3-day hard freeze they took the engine apart and sent me a bill for all the freeze damage + winterization. The total bill to bring it back online was 3x the purchase cost of the boat. When I showed up next summer and confronted the manager on his negligence and failure to inform me of the delay he lawyered up. Tell me again why I don't trust boat yards....

 

[dubs283]

Re: 165 Mercruiser Leaking and no Forward

If it engages using the engine connector it is a shift cable adjustment issue...fixed by rotating the cable lock-point (plastic or brass barrel-like thing) to the direction of the FWD, like 2 turns at a time until all gears are achieved from shifting at the control box.

that is NOT the correct way to adjust the lower shift cable

it is set at 6" in FWD gear with the end stud at the bottom of the slot, if you can't get REV, sometimes you can adjust the stud in the slot but if you can't achieve REV - replace the cable

 

[dubs283]

Re: 165 Mercruiser Leaking and no Forward

Water coming in the boat by faulty bellows is not something to let go. The u-joints, gimbal bearing, yoke seal, etc will be very short lived

not to mention the water enterning the drive and thus destroying the internals

Ancloter:
usable boat with a hole in the bellows?? - NOT!!!

what if you are out and the engine dies and pump fails??

 

[Ancloter]

Re: 165 Mercruiser Leaking and no Forward

what if you are out and the engine dies and pump fails??

Lol. Yeah, that'll happen

The leak was less than a gallon an hour. I'd have died of thirst first. It was a bowrider I used for inshore fishing and trailered after use. I'm more uptight about things nowadays since I'm not in my 20s anymore and go beyond 60 mi.s for fish. PLB, VHF and a boat with no leaks.

 

[Ancloter]

Re: 165 Mercruiser Leaking and no Forward

that is NOT the correct way to adjust the lower shift cable

it is set at 6" in FWD gear with the end stud at the bottom of the slot, if you can't get REV, sometimes you can adjust the stud in the slot but if you can't achieve REV - replace the cable

He said he couldn't achieve FWD, not that he was installing a new cable and needed to set it. That's the adjustment you provide, initial cable install setting. And replacing a cable for not being able to achieve REV is ridiculous. Why impart a $40+ replacement if the cable is still good? The proper adjustment for stretched cable is to remove the end cap and cut it to the spec. length to take up the additional slack.

He said he can't achieve FWD. So it is either a stretched shift cable or, more likely, mis-aligned shift splines from a prior removal/reinstallation of the lower unit. My shift cable adjustment advice addresses the more common shift spline mis-alignment as opposed to the less common worn shift cable or the cable install setting adjustments.

It's either a mis-aligned shift spline or a worn cable. Neither of which typically require installing a new cable -which won't address mis-aligned splines anyways. As you know there's typically 30' or more of slack in the N on the shift cable in the L unit and some people install the lower unit in N rather than FWD. Adjusting the shift cable at the engine and control box will correct a shift cable mis-alignment. Or the lower unit can be pulled and Trial and Error can be used to recenter the splines to attain all gears from the control box. On an Unknown engine it's best to start with the cable adjustment as Prior Owner may have been adjusting them anyways.

 

[165mercruiser]

Re: 165 Mercruiser Leaking and no Forward

Thank you everyone for your replies. It has helped a lot. When I was running the boat out of the water with muffs I noticed that water was comming in from the Heat Exchanger. After careful review I noticed that one of the 2 Pipe Plug was missing. So now I am waiting for a Pipe Plug to arrive tomorrow. Once I install the Pipe Plug I will run the motor with the muffs and check that no more water is comming in from the Heat Exchanger. Once that is resolved I will investigate whether there is water comming in from the bellows. I believe in order to check this I will have to put it in the water. Is that correct? I read you can also fill the back end of the boat and tilt it so see if water is comming out the back. Do you think this would work?

 

[dubs283]

Re: 165 Mercruiser Leaking and no Forward

He said he couldn't achieve FWD, not that he was installing a new cable and needed to set it. That's the adjustment you provide, initial cable install setting. And replacing a cable for not being able to achieve REV is ridiculous. Why impart a $40+ replacement if the cable is still good? The proper adjustment for stretched cable is to remove the end cap and cut it to the spec. length to take up the additional slack.

He said he can't achieve FWD. So it is either a stretched shift cable or, more likely, mis-aligned shift splines from a prior removal/reinstallation of the lower unit. My shift cable adjustment advice addresses the more common shift spline mis-alignment as opposed to the less common worn shift cable or the cable install setting adjustments.

It's either a mis-aligned shift spline or a worn cable. Neither of which typically require installing a new cable -which won't address mis-aligned splines anyways. As you know there's typically 30' or more of slack in the N on the shift cable in the L unit and some people install the lower unit in N rather than FWD. Adjusting the shift cable at the engine and control box will correct a shift cable mis-alignment. Or the lower unit can be pulled and Trial and Error can be used to recenter the splines to attain all gears from the control box. On an Unknown engine it's best to start with the cable adjustment as Prior Owner may have been adjusting them anyways.

where to begin??

cut the cable?? - maybe 30 years ago when cables had to be cut to length when new but now times are a different

the setting for the cable is 6" and thats it - no more adjustment, if the cable is stretched its done - you can cut it if you want but its not the CORRECT way to fix the issue

if the splines are off on the shift shaft you will NEVER get it to shift properly by adjusting the cable

trial and error to align the splines?? sheesh!!

don't know where you get your info from but its WAY off

 

[Ancloter]

Re: 165 Mercruiser Leaking and no Forward

where to begin??

cut the cable?? - maybe 30 years ago when cables had to be cut to length when new but now times are a different

the setting for the cable is 6" and thats it - no more adjustment, if the cable is stretched its done - you can cut it if you want but its not the CORRECT way to fix the issue

if the splines are off on the shift shaft you will NEVER get it to shift properly by adjusting the cable

trial and error to align the splines?? sheesh!!

don't know where you get your info from but its WAY off

Yes, where to begin lol

-30 years ago reputable mechanics did not impart unnecessary costs to customers. But, as you say times have changed I suppose. All boat owners these days are multi-millionaires -or should be -or eventually will need to be.

"if the splines are off on the shift shaft you will NEVER get it to shift properly by adjusting the cable"

-Say what? If a boats at the dock are you going to go swimming or insist the owner pulls it to re-align shift splines? :facepalm: It's quite easy to do starting at the shift lever at the engine with the cable disconnected. Not preferred of course but do-able to get the owner running again. But that's not necessary in this case since the boat is out of the water.

Having discussed all this why don't we give him a do-able solution based upon reasonable assumptions and minimal costs?

My recommendation:
-Shift into FWD
-Drop the lower unit
-Using a vice grip or similar shift the lower unit into FWD and confirm it is in gear by turning the drive shaft.
-By hand turn the shift shaft back in the direction of N but do not shift it. Just rotate it back until it stops to take up the slack.
-Re-mount the lower unit.
-Check for proper shifting.
-If shifting is off: Start a new thread.

Regards.

 

[Ancloter]

Re: 165 Mercruiser Leaking and no Forward

Thank you everyone for your replies. It has helped a lot. When I was running the boat out of the water with muffs I noticed that water was comming in from the Heat Exchanger. After careful review I noticed that one of the 2 Pipe Plug was missing. So now I am waiting for a Pipe Plug to arrive tomorrow. Once I install the Pipe Plug I will run the motor with the muffs and check that no more water is comming in from the Heat Exchanger. Once that is resolved I will investigate whether there is water comming in from the bellows. I believe in order to check this I will have to put it in the water. Is that correct? I read you can also fill the back end of the boat and tilt it so see if water is comming out the back. Do you think this would work?

At least one of those pipe plugs in the heat exchanger is a drain petcock for winterization. Make sure at least one is installed. You might find the missing one by looking around and in the bilge. Install with Teflon tape since these fittings are occasionally replaced. The heat exchanger was an upgrade in those years btw. Consider yourself lucky. I had to plumb one into mine.

-RE: Bellows. From the last picture you posted it looks like you have a leaking transom rather than bellows. You'll need to launch the boat to verify where it's coming from. If you fill-tilt the boat you'll dump water into the starter, etc. and it could also damage the boat.

-If it's the bellows, tighten or replace the bellows depending on its condition -it's the black rubber 'accordian thing' under where the outdrive goes through the transom. You'll have to pop the outdrive to replace it. Merc recommends replacing the bellows every 5 years btw. If you see cracks or holes in the rubber it's time to replace it.

-If it's the transom you could try caulking inside and out with an acrylic caulk and see if that works. But a rotted transom usually has two solutions: rebuild the transom or sell the boat. Most people opt for the latter. Otoh I am somewhat sentimental and chose to replace the transom on one of my boats. Some people freak out at a rotted transom, convinced operating the boat or attempting to repair it is akin to suicide and a threat to society.