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2003 50 B3 issues overheat amp carb

C

cruzanron

New member
"I rebuilt my carbs last weeke

"I rebuilt my carbs last weekend and sealed up the engine covers which had been needing repair. I water tested yesterday and port engine overheated after 5 minutes at cruise. I shut it down immediately but it would not start again. I thought that maybe with new sealed engine bay covers it was not getting as much air as before, but it is now operating as designed and should be fine, right? I was told that I needed to adjust the carb after rebuild & that I also probably have a bad impeller. Impellers last changed a little more than 2 yrs ago. Does this sound right? If so, how do I need to set the carb and is the water pump assembly on the engine the only impeller? (no impeller in the lower unit?)"
 
"Bravo 3s dont have lower g/b

"Bravo 3s dont have lower g/b impellers matey. Check cooling from inlet(holes on lower gearcasing of leg) or seperate thruhull (if modified) right thru pump, thermostat, and heat exchangers to exhaust/exit obstructions, (water and gasses)"
 
"Engine cooling does not depen

"Engine cooling does not depend on local* air. What the engine does need some airflow for is for combustion, i.e., for the carb. Look per "Benj" for you cooling problem. The only real "carb" adjustments are for idle speed/mixture. Unless you screwed up the (main)jets on one of the carbs and you are runnning excessively lean (and hot) don't think its a carb problem. Other possibilities: Plugged exhaust elbows (corrosion or stray bits of the old impeller) reducing water flow; Impellers can die in seconds if they suck up sand/gravel or are run dry. You also could have gotted a plastic bag pasted up on the drive grill inlet.
I personally HATE thru-drive water inlets and unless the drive REQUIRES that water flow thru the drive for cooling of the drive, I always modify my boats for thru hull pickups w/strainers.

*PS..this is a VERY strange board. Instead of using the word "local" in my initial post, I used the very technical term that starts with an "a" and is followed by an "mbi" and ends in "ent". I got a popup saying that this word was "not allowed on this discussion board" ????"
 
"Assuming that the carb is ok

"Assuming that the carb is ok and it is the impeller, how do I know if I did permenant damage to the engine? It won't start, but turns over ok. Also, how/if do I convert a 5.0/B3 to a thru-hull cooling system? I have an old seacock in the boat that is closed and not used (about an inch or 1.5 dia). Could I use that ONE for both engines and is there a conversion kit on the market that I can get? I also looked at an exploded view of a B3 drive and I did not see that the drive used seawater for cooling. Is that your understanding as well? You advice is very helpful. thanks."
 
"If your total operating time

"If your total operating time was 5 mins, you have a fair chance of no permanent damage from the overheat unless some permanent damage "thing" caused the overheat. You do need to find out "why"

You probably can't use that seacock.
While you can use one inlet for both engines, I would not. Its a much easier design if you use one per engine. Check the internal diameter of the hose to your raw water pump. All the plumbing from there to the thruhull needs to be at least that size. If your hull is solid glass, then its a DIY job. If its a cored hull, then I'd leave it to a pro. There are a number of inlets especially designed for this purpose. You should use one with some sort of grill on the front. You need to have a 1/4 turn (lever) shut off valve immediately inside the thru hull. There should be a backing plate ("star-board", available any marine store) inside the hull on the thru hull which should be "bonded" electrically to the engine. There needs to be bedding compound between the backing plate and the hull. Depending on your hull design the "scoop" on the raw water inlets should either face straight forward, or if its a planning hull with a "V", canted inward towards the keel slightly. All metal hardware should be bronze. Double clamp all hoses, use wire reinforced hose for the hose. I'd serously consider strainers on the water lines. Locate them where you can get at them to inspect and clean them out on daily basis if you have to.
BTW, when you drill that largish hole in the hull for the inlets, coat the exposed sides of the holes with epoxy, and let it harden. My druthers for that hole is about in line or a few inches forward of the front of the engine. In your case, both inlets shuld be "outboard" of the engine. They should be fairly low on the hull, but not dead on the bottom. Snoop around your marina yard and look at some straight inboard powered boats.

Re: water cooling of drive. I don't know that much about your particular drive, wiser heads on this group do."
 
"Thank you. I was idling in a

"Thank you. I was idling in a no wake zone for about 15 minutes then got up on plane for about 5 when I shut it down and smelled smoke (burning oil from carb and other unknown areas) Prior to that, I warmed the engines on the trailer with earmuffs for 10 minutes before going to the ramp. I really hope I didn't blow the engine. Any way to easily tell?"
 
"Robert:

I have had the sam

"Robert:

I have had the same problem occur w/words like "cat". Your word (which I could not post) is one of those "dangerous" big words not allowed by the security filter on this site! Of course some squirrely characters such as the recent pissandmoan.com idiot slip by the security filter . But, idiots are allowed.
uhoh.gif
"
 
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