Hit Rock with 350/Cobra Bayliner...Engine Troubles

[Chris5280]

I'm a newb to boats and the forum. Recently purchased a Bayliner Capri with a newly rebuilt 350 mated to a rebuilt OMC Cobra outdrive. Ran great... Took to Powell last week and bumped a submerged rock at wakeless speed. Saw it at the last second and killed engine/trimmed up but did have a little scraping on a plastic (yeah I know) prop. No evident damage otherwise.

Got into open water and tried to restart engine, but it wouldn't start with throttle in idle position. In fact, I only got it to start at all at full throttle, but every time I throttle back to engage gears it dies. Eventually I had to start in gear at nearly full throttle- bad idea, I know- in order to get out of the canyon and back to the marina. Ran fine at anything over half throttle, but burned through an obnoxious amount of fuel as well, to the tune of 4-5 gallons / mile.

Trailered home and tried on the lake here once more- same issue. I would think that I bent the prop shaft, but the issue exists whether the boat is in neutral or in gear, so that seems unlikely. Read a lot on this forum but don't see anyone with quite this problem... help!!

Thanks guys...

 

[Howard Sterndrive]

Re: Hit Rock with 350/Cobra Bayliner...Engine Troubles

sounds like carburetor issues - choke not opening possibly
also check yellow/clear hose from fuel pump to carb - if it has any gas in it, you need a new fuel pump

on a marine fuel pump, if the diaphragm ruptures, lots of gas dumps through that hose into the carb

I'm having a hard time connecting it to the rock scrape thing....

except... maybe the shift cable got knocked out of adjustment and now the ESA switch is staying engaged. You can try adjusting the shift cables to spec and watching the ESA switches as someone shifts in and out of gear.

p.s. there should be a neutral safety switch in your shifter that prevents starting in gear. You want to reconnect that - sounds like it has been bypassed.

 

[Chris5280]

Re: Hit Rock with 350/Cobra Bayliner...Engine Troubles

Thanks for the quick response.

You referred to a yellow/clear hose running to the carb. Is that the black hose with the red cable ties in the attached pic? Restarted the engine on muffs and fuel is dumping into the carb through that hose. Should this be happening, or does it indicate a ruptured diaphragm as you indicated?

(Sorry, while I am pretty competent with fuel injected engines, I have zero experience working on carbed engines:-/)

Thanks for the help!

 

[Idlespeedonly]

Re: Hit Rock with 350/Cobra Bayliner...Engine Troubles

That is the hose. It seems your pump is bad.

 

[Howard Sterndrive]

Re: Hit Rock with 350/Cobra Bayliner...Engine Troubles

you can buy the clear/yellow stuff at any place as snowmobile or motorcycle fuel line. that way you can see what's up with it.
also not usually clamped on - almost as if it was blowing off it's leaking so bad and someone clamped it

 

[Reinell-BRXL-191]

Re: Hit Rock with 350/Cobra Bayliner...Engine Troubles

Thanks for the quick response.

Restarted the engine on muffs and fuel is dumping into the carb through that hose. Should this be happening, or does it indicate a ruptured diaphragm as you indicated?

If there is fuel flowing in that hose, that explains your problem, the diaphragm has failed, and is now putting the leaking fuel in to the carb, this would of course cause a very rich condition and flooding... so, it working at higher RPM is because the engine is trying to digest the extra fuel, but at lower RPM it is flooding the engine. So, a new fuel pump is in your future.. and good for you that it has absolutely nothing to do with you hitting a rock.. it is just coincidence. Make sure you replace the pump with an exact like pump made for a marine application and don't try and use one made for a car (fire hazard) - and get that hose replaced with a clear one, (fuel rated) so you can see when this happens the next time...

 

[Chris5280]

Re: Hit Rock with 350/Cobra Bayliner...Engine Troubles

Ordered a Carter Marine fuel pump this morning...Sounds like it should fix the problem but I will post back with resolution when it comes in and I install it next week.

Thanks, guys!

 

[Chris5280]

Re: Hit Rock with 350/Cobra Bayliner...Engine Troubles

So, I replaced the fuel pump and she started right up and seemed to run fine on muffs. Put her in the water and am having trouble running at idle still. Removed flame arrester/air cleaner on carb (mostly to see what the choke was doing) and she runs much more smoothly. Weird part- when I screw in the center post that the flame arrester bolts onto back in, she sputters and dies. WTH? Also a power issue as I could only hit about 2500 RPMs at WOT and boat would not plane. Prior to this issue 3500-4000 was normal.

Any thoughts? Maybe this all wasn't the fuel pump?

Thanks for the help!

 

[arc68]

Re: Hit Rock with 350/Cobra Bayliner...Engine Troubles

Check fuel filters may have trash in last chance filter in carb.

 

[Reinell-BRXL-191]

Re: Hit Rock with 350/Cobra Bayliner...Engine Troubles

I would want to check and make sure the carb and final filter are not being blocked with small rubber bits from when the fuel pump diaphragm came apart

 

[Chris5280]

Re: Hit Rock with 350/Cobra Bayliner...Engine Troubles

The saga continues, unfortunately.

I replaced both the spin-on fuel filter/water separator and also the last chance filter at the carb. Now, the engine doesn't start at all, the carb filter appears dry and the spin-on filter has very little fuel in it, while the old one was full of fuel.

I've pumped the throttle lever a number of times to "prime" to no avail. She turns over but doesn't start.

Thoughts?

Thanks...

 

[Scott Danforth]

Re: Hit Rock with 350/Cobra Bayliner...Engine Troubles

if your carb bowls are dry, pumping the throttle wont do anything.

dribble a few drops of fuel down the carb then try to start. is sounds like you dont have fuel from the pump to the carb yet.

and yes, if you had fuel coming out of the safety line, you needed to replace your fuel pump.

the engine dieing while installing the flame arrestor indicates to me that your running rich to begin with and adding the flame arrestor just makes it worse.

a few things after you replaced the fuel pump:
did you replace the plugs after running that rich?
did you change oil after dumping that amount of fuel in the engine?

 

[Chris5280]

Re: Hit Rock with 350/Cobra Bayliner...Engine Troubles

OK. So, I filled the fuel filter with fresh fuel, reinstalled, and eventually was able to get the boat started. However, I still have idle/stall issues and very limited RPMs at WOT.

Here is what I've observed, however. I removed the flame arrester and watched what happens. At an idle, the front/primary choke opens very little. When I assisted it by hand, the engine idled much more strongly, the choke plate stayed open itself without my continued assistance, and the stalling issue was gone.

Then, I increased to WOT. Similarly, the secondary choke plates did not open and consequently, ~2000rpms, boat would not plane, etc. When I assisted it by hand, I had plenty of power and was getting 4000+ RPMs.

What should be happening to open those choke plates? It is a throttle cable in need of adjustment? (If so, how did I do that and to what specs?) It seems like there is more going on, though, than a direct link from throttle control lever to choke plates.

Thanks again for all the help.