OMC I/O first test drive, need some part names.

[Justin_S987]

Hello, it's been awhile since I last posted and my 1980 OMC 120 Renkin, has come a long way. I put it in the water for the first time this past week and after 4 hours re-learning that you have to adjust your carburetor for higher attitudes on mountain lakes before it will run.......... My girlfreind and I had an otherwise very enjoyable putter around a large lake...until the alternator belt broke on me, ending our fun. I was staying close to shore and happen to be back near the dock so it didn't run long without the belt and I shut it off and drifted as soon as I pointed the boat back towards shore. (A moment later, I checked it with my IR thermometer at the block between the carb and valve cover, its was at 203°)

Anyways, during our shakedown run, I made note of a few minor probelms and now need some part names so I can find what I need.

First of all, the belt. I have the belt part number, OMC 311606-C, but I'm not finding an exact match, although there are lots of good alternatives in the form of standard and cogged belts on amazon. However, I can't seem to identify the length of belt accurately, I can tell it's a 3/8 bealt, between 37" and 39" but the original stretched real bad near the break making it difficult to gauge.

Second, overall, my 40yo boat does not leak which is nice, aside from water lapping into the bilge through the shift cable tube on the intermediate housing. I assume there is supposed to be some sort of grommet to seal that tube but I can't find a reference for it. So knowing what seals the shift cable pass through would be a big help.

Lastly, my boat has canopy hoops that are in decent shape but the plastic slides they attach to inside their tracks are cracked and broken making it difficult to put up. Can these be repaired or do I need to look into getting new tracks for my canopy?

 

[Bt Doctur]

most just pass the cable thru a hose that is threaded into the transom housing
number 40

 

[Scott Danforth]

Did you do all the drive service?

Raw water impeller? Ball gears?

 

[kenny nunez]

Google Taylor Made boat tops and hardware.
They have everything you will need to repair the slide hardware.
As far as the belt you will just have to experiment which one is correct. Take a close look at the pulleys for rust. That always kills belts and the dust from the belt will end up getting sucked to the flame arrestor.
With the drive raised look where the cable enters the intermediate housing, there should be a stainless loop held with a bolt to retain the cable. The cable should have a rubber sleeve that seals the cable in the housing. Sometime the rubber is gone so try plugging some silicone to seal it. Do not even think about replacing the cable, very expensive if you can even get someone to replace it.
If your ball gears have more than 50% on them just keep on using it as it is.
If any thing in the drive lets go it will be cheaper in the long run to replace the drive platform if you really like the boat.

 

[Justin_S987]

Did you do all the drive service?

Raw water impeller? Ball gears?

Yep, I replaced the ball gears and drive shaft seals this past spring and I rebuilt the upper gearbox assembly with a brand new top pinion gearbox and shaft plus shimmed it, a new water pump empeller with housing, and a new middle drive shaft. I also went to the effort to find permatex #2 to seal it all according to the OMC service manual. I drained all the gearboxes for the lift motor, worm gear, upper housing and lower housing and put green 90w in all 4 places.

I gave the engine an oil change and new filter, replaced the leaking manifold drains, checked all of the hoses, tuned the distributor and replaced some broken bolts on the thermostat housing. I also installed an inline fuel bulb to help manually draw fuel up from the tank to start it.
The steering is good but I had to reattach and adjust to throttle cable which seems to be too long by about a foot, so it leaves a big loop of extra cable sitting by the engine.

Uh, what else, all of the necessary electrical stuff is there and works but the lights are intermittent and wonky and I don't know why, maybe bad switches.

 

[Justin_S987]

Google Taylor Made boat tops and hardware.
They have everything you will need to repair the slide hardware.
As far as the belt you will just have to experiment which one is correct. Take a close look at the pulleys for rust. That always kills belts and the dust from the belt will end up getting sucked to the flame arrestor.
With the drive raised look where the cable enters the intermediate housing, there should be a stainless loop held with a bolt to retain the cable. The cable should have a rubber sleeve that seals the cable in the housing. Sometime the rubber is gone so try plugging some silicone to seal it. Do not even think about replacing the cable, very expensive if you can even get someone to replace it.
If your ball gears have more than 50% on them just keep on using it as it is.
If any thing in the drive lets go it will be cheaper in the long run to replace the drive platform if you really like the boat.

Oh yeah, the alternator is pretty ugly, I was thinking about replacing it with a coated one that matches from a later Mercruiser but its 120amp output vs the original's 50 to 65amp output.