is it broke or not?

[serisdaddy]

I just bought a 88 thunder craft with a 4.3L omc cobra. It runs great sitting still but going it sputters and doesnt seem to be geting full throttle and the boat fills with water. The pump keeps it under control for the most part but not really. If the pump is off it would probably sink:'( Anyway there are two rubber boots on my outdrive. The top one seems in good shape no dry rot or anything but the lower one has holes all along it on the bottom half. I put my finger in there and there is nothing going through it. I was told that the holes were worn spots but they are perfectly uniform as if placed there on purpose...is it broke and need to be replaced or is it how its supposed to be? And what would cause it to sputter I can only go between 25-35mph at about 25hundred rpms. My oil pressure it at 40 unless it is full throttle then shoots to 80-90 and I have messed with the trim and it doesnt really help.

 

[Gary H NC]

Re: is it broke or not?

The holes are in your exhaust bellows...that is normal.
The first thing is to find the water leak.
look at the power steering cooler on the starboard side of the engine,that could be leaking.it could be u-joint bellows leaking or a number of other things.
Find the leak first then address the engine sputter.
It could have freeze damage that is causing both problems.

 

[bruceb58]

Re: is it broke or not?

i woud find the water leak before you do anything else.

If you have a hole in your upper bellows, that may explain the water you are getting in your boat. If you have a hole in these bellows, you probably also have water in your drive's gear oil too. If this has been happening for awhile you may have big problems with bearing/gear failure in your drive.

 

[Boatist]

Re: is it broke or not?

I would not put it in the water until you find and fix the water leak. Water in the hull bad for stirngers, motor, steering, floatition, and the life of your boat and family.

Then you can address the motor problems.

 

[serisdaddy]

Re: is it broke or not?

I checked my gear oil today from the bottom of the prop and it came out thick and greenish in color...I dont know what color it is supposed to be but it doesnt look like there is any water in there at all.

I also tried to change the oil but can not find the oil filter or a drain plug...any ideas?

 

[serisdaddy]

Re: is it broke or not?

I checked my gear oil today from the bottom of the prop and it came out thick and greenish in color...I dont know what color it is supposed to be but it doesnt look like there is any water in there at all.

I also tried to change the oil but can not find the oil filter or a drain plug...any ideas? regular motor oil that is

 

[Don S]

Re: is it broke or not?

I also tried to change the oil but can not find the oil filter or a drain plug...any ideas?

Find a marine mechanic.

 

[Boatin Bob]

Re: is it broke or not?

Welcome to the world of marine engines, if you choose not to take Don's advice and want to do it yourself then you need to buy an oil change pump. There is no drain plug because you normally can't get down there with anything to drain it into. The pump will slide a thin tube all the way down the dipstick tube to the pan and then you suck the oil up with the pump. Oil needs to be warmed up (engine run) to make it easier. The filter is there most likely near the back down low on the engine, you will need to learn how to stand on head and contort body into impossible positions in order to see/reach it, also another tip for the filter is to put plastic bags around it because guaranteed you won't get it off without spilling some oil and you haven't been a boater yet if you haven't tried cleaning up dirty oil out of the bilge. Get used to working blind as well because some things you can only touch, never see....good luck!

 

[serisdaddy]

Re: is it broke or not?

Boatin Bob or anyone who knows...what do you think of the greenish gear oil? there doesnt seem to be any water in there it is thick and no bubbles or oily look like thered be if water was present

 

[Boatin Bob]

Re: is it broke or not?

The green stuff sounds like a Merc product not OMC (more honey brown) so as long as no shavings and no apparent water in there causing it to go milky I would think you are OK.

 

[serisdaddy]

Re: is it broke or not?

sweet...I think I am ok I took youre idea (boatin Bob) and went to the marina. Unfortunately I spent 300 bucks on a manual oil pump gear oil (merc... which is a bluish green) a gear oil pump and some other misc. stuff I may need. All and all I cant thank you enough for being as patient and kind to a new ignorant boater, but thanks to you all I will maybe be a boater for some time to come. Thanks alot

P.S. Anyone who reads this.....
BOATIN BOB KNOWS HIS BOATS

 

[Gary H NC]

Re: is it broke or not?

The oil filter is on the port side of the engine torward the rear below the head.
Look at where your oil dipstick goes in.It should have threads on the tube for the size of a garden hose.
I use a Balkamp pump from Napa- part # 770-5028- it hooks to a drill and will pump the oil out in about 2 minutes.I rigged up the hose for the pump with parts from the hardware store for about 3 bucks.All in all i got a great oil change pump for very cheap.
Bob is right on about the gear oil,green is Merc oil.
It will work fine or you can get CRC hi-vis gear lube from Napa that is supposed to be the same as the original OMC lube.
That model 4.3 will hold 4.75 quarts with filter.

 

[Boatin Bob]

Re: is it broke or not?

Just read that you bought a gear lube pump as well. Please read this about changing the lube on a Cobra. The drain screw is down at the bottom stbd side of the lower unit unit (bullet) when you take it out it should have a magnet on it, check for metal, fine stuff is ok (almost like fur) big pieces are a no no. After taking that out remove the diptstick screw way up on top of the drive, takes a while to drain as it's pretty thick stuff. Once drained put the drain screw back in and remove the fill screw about half way up on the stbd side (same kind of screw as the drain). Set the dipstick screw back in but don't screw it in. Attach your lube pump now and pump it until the lube comes up to the fill line on the dipstick. Your drive will hold 64 oz so anything less, either you have air or it wasn't totally empty to start. Very important to do it this way to avoid large air pockets in there as they work up to the top and then the upper gears won't be lubed and will become toast very quickly. See this link for an exploded pic of the lower unit item 53 is the drain screw and item 41 is the fill screw. Cobra Lower

 

[serisdaddy]

Re: is it broke or not?

when I drained the gear oil just to check for water there was very fine metal flakes dust really on the magnet. Thanks for the walk-through on changing the gear oil I can def. use it