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b89 CobraWater not reaching Engine

J

JoshuaMcCoy

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"I went to flush some water th

"I went to flush some water through the boat engine today and found that there is no water circulating through the engine. I took off the impeller which looked ok. I replaced it anyways since I had an extra kit laying around (replaced impeller, o-ring, thrust plate, and the cup the impellor sits in. I then ran the hose with the impellor off and water gushes out of the feed hole. I took the water feed hose off of the engine and ran water down that and water gushes out of the impeller exit hole. I figured everything was fine, but when I put it all back together I left the feed hose for the engine off and started the engine and nothing came out. Any ideas?

BTW it has a 302 engine."
 
"Hi Joshua, Scott;

I am new

"Hi Joshua, Scott;

I am new to this site but have the same problem as you have, Joshua. My (pontoon) boat has a 2.3 litre with the Cobra outdrive. I recently purchased it knowing I had to have the upper unit rebuilt. However, when they rebuilt it, they must have misaligned the water tube or lost a seal when putting it back together. Not only that, they forgot to put the wear plate and gasket back in place behind the impeller.
I was not getting any water up the intake hose to the thermostat housing. I attempted to use the ears to supply water but had water streaming out of the three, small 1/8 inch drain holes in the lower unit. I then used a half barrel to immerse the lower unit into. At low rpms, nothing really happens. At higher rpms, it appears to bubble up around the intake port holes in the lower unit. It appears to me that the exhaust is pushing the water out of the unit at higher rpms, while at lower revs, there is just enough pressure to prevent the water from being drawn up the water tube. Any thoughts? Getting exasperated!"
 
Hey Guys. You might first want

Hey Guys. You might first want to take the hose off coming from the oudrive; start the engine for only a few seconds and see if water is pumping up.
If that works then what you want to do is check your lower unit lube and see if there is any trace of water or moisture. If there is you want to pressure test the outdrive. Take the outdrive off and place it so it is submerged in water. I used a cement tub but anything that will work. Then use something that will put out air either a air compressor set very low or preferably a foot pump like for a bicycle. Connect the air to one of the lube drain screw openings and pump to about 25 pounds. Look for the bubbles which will tell you where its leaking as you do have a leak which keeps water from pumping through.
Common places are the prop seal or the o-rings in the lower housing.
 
"Paul,

Thanks for your sugg

"Paul,

Thanks for your suggestion. Finally got back at working on the boat recently. I haven't ventured to remove the outdrive since but did bring the boat bakc to the mechnaic who worked on it.

Summing it up so far - got some water to the engine from the impeller (I took hose off engine to check flow), but flow drops off to nothing at ~1100 rpm, but returns after 10 seconds or so at higher rpm (2500-3000). On the following day, got good flow at 600 rpm with water line off, then reconnected it and ran it for 10-15 minutes and temp stayed at 140 deg. Took it for a ride for 10 minutes, ran up to 150 f, then started to heat up to 190 f.

Not sure where the problem is now! Seems like the problem is with the water supply from somewhere before teh engine as flow is good one time, bad another, inconsistent. Ideas?"
 
"Could still be an air leak at

"Could still be an air leak at the water pump or an internal leak (seals) as I suggested before.
Have you checked the lube for signs of moisture? That would be the first thing as it will tell you if its internal. Also not sure if already done but the LAST thing I would have done after the mechanic was done is change the entire water pump in the outdrive. Not just the impeller.
Also have you checked for any blockage in the manifolds? How old are the manifolds/risers and what type of environement has the outdrive been subject to? fresh water, salt, etc."
 
"Paul,

I will check those i

"Paul,

I will check those items this weekend. Although it is a 1989, it does not have a lot of hours on it and when I winterized it last year, there did not seem to be any blockage in the manifold (inserted awire through the brass drain cocks). That being said, Ill check again. The boat has only been in fresh water (Northern Ontario). I looked at the outdrive at the shop when the mechanics had it apart and it looked good.

Since the boat did run for a while then overheated, you may be right in that the manifolds are plugged. I'll check the flow to the engine first thing to see if it good at low/high rpms. If it is, then likely the manifold???

From the first time the mechanics on it, the noise coming out the exhaust is loud. It was not like that when it went in to the shop. I suspect it is moslty due to lack of water muffling the sound. Would this alos be linked to manifold issues?

Thanks."
 
"Rob, when you check the manif

"Rob, when you check the manifold for a blockage, I would remove the pet cock . That way you can really see if there is a blockage (useing your finger)"
 
"Thanks Kevin,

Checked the

"Thanks Kevin,

Checked the manifold and seems there is no blockage. A neighbour of mine who used to own a marina suggested some checks on the mainfold. The torques on the nuts/bolts was well below spec so I torqued them to 30-35 ftlbs.
Manifolds, block etc are all 1989 as far as I know from the numbers, but look in quite good condition and reportedly had few miles but well maintained previously. No rust stains or exhaust leak stains on the manifild or block. In fact, it is all clean and looks near new (clean original paint, nuts/bolts clean - no rust....),
I broke down and brought it to another marina and will have the mechanic check things over- including taking apart the bottom end. Will let you know the outcome in a week or so,hopefully less."
 
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