HELP 1987 Four Winns 215 Sundowner-Engine Knock at High RPM/Load With Video!

[Keithmanlite]

Purchased the above mentioned boat, took out twice before buying, no problems. This is 305 Alpha 1 system. After taking ownership, problem started occurring. Once motor warms up I hear loud knocking above 3300 RPM. I can back the system down to idle wait a minute and start up again as long as I stay under 3500 RPM problem stays at bay. Originally thinking ignition problem, changed wires, plugs, coil and am going to do cap and rotor. At one point I took the 17 pitch prop off and put on a 20 pitch thinking I could get more speed with less drag. This made problem worse boat wouldn't maintain 3K, no matter what I do the problem keeps apparently getting worse. I have uploaded a video which contains the audio I feel is important http://youtu.be/mgWacR1N4qE . you can hear the motor all of a sudden loose power then knocking starts. I don't know what this is. I want to get a plan to work on boat over winter and restore as much as possible the boat to its original power and speed. I am new to boating and power systems, I am familiar with car engine repair and maintenance. The boat starts and runs great in driveway and at the launch. Turn the key starts immediately and idles between 6-800 Rpm. Like I already stated am going to do cap and rotor next, am planning on checking timing if I can find scale and mark, but don't understand how timing could shift when warmed up

Any advise greatly appreciated, hoping I didn't get a lost cause

 

[JaCrispy]

Is it knocking or backfiring through the carb? Hard to tell from the vid. I had a similar issue with my boat, turned out to be the rocker arms.

 

[bilge rat jim]

That sounds like you're dropping a cylinder or two - probably ignition related. You have the right idea, start with replacing cap, rotor, pugs and wires. Make sure the pick=up coils on the ignition sensor aren't corroded.

 

[NHGuy]

Also make sure it isn't timed with too much advance or running hot. That could be detonation if one or both of those conditions is there.
Definitely do the ignition parts, time it to 8 or 9 degrees BTDC at 725 rpm. Then give us a report.
Don't run it like that, bad for hard parts.

 

[airdvr1227]

I'm hearing backfiring through the carb. That's many times a lean condition. You aren't getting enough gas to the carb. Causes? Check this thread for a pretty good start. Good luck and keep us posted.

 

[Keithmanlite]

changed cap and rotor, both badly damaged I will attach pictures, but I also changed gas water separator. I also read on this forum that someone had a wellcraft where he found oil level was to high and was causing hydraulic lifting of lifters. He drained oil and carefully added on what was called for and his problem went away. I started the boat in the driveway after each change . Nothing changed until cap and rotor, and boy did it change. I thought it ran well before but it smelled rich. Not the case anymore. Still I have to get it out on the water, tomorrow Sunday the 7th, we are going to open her up

 

[Keithmanlite]

thanks for all the replies, going out Sunday to try. From that point I am going to check timing.
haven't done that since my Malibu which I think I still have the distributor wrench. I don't know what happened to my inductive pickup timing light may have to buy another. Either way when I was in there I wiped off the scale and cleaned the groove on center hub so I will be able to see it. Gradations are gone but should be able to get a picture online and reference it to the scale

Thanks again everyone ...... will report back Sunday Night

 

[redneck joe]

you will find your light as soon as you buy and use your new one.

 

[Keithmanlite]

okay cap was definitely part of the problem, took the boat out had it at 4K a good 10-15 minutes no problem. Then we started going through some pretty big swells and all of a sudden it happened again. But this time it actually sounded like engine noise not ignition. Called mechanic and asked him to take a ride with me later this week. One of my stipulations when I bought the boat was I wanted the mechanic that has worked on it since it was new to continue to work on it. This time it sounds like something clunking but it still goes away. when I give it a minute and get going again it stays away until above 3500 RPM, unless I start hitting waves and stress the motor.

 

[Keithmanlite]

Well here is the skinny, for what its worth I feel something major is wrong but did what I always do. Start inexpensive an keep going till you cant.
Took the mechanic out Yesterday. Kept the boat on the trailer at the launch. He found we had exhaust inside engine compartment. Smoked the engine and couldn't pinpoint but looks like gasket on Y adapter. Motor ran really strong didn't make a sound at the dock. Took boat out on the lake had it running at 43 MPH and 4600 RPM. Boat ran like that for a couple minutes then oil pressure starts dropping 60, 40, 25 psi and knocking. Idle motor back sit for a minute everything goes back to sounding great and working good up to 33-3500 Rpm. Long story short I am being told pull motor probably main bearing overheating looses pressure, no oil to top end, valves start clacking banging starts. Here is where I would love to hear ideas. doesn't make sense what it does. Engine guy says he can make it better than ever but $2800, Mechanic says he can get a 350 instead of 305 reuse all parts I just put in and get me up and running for next year. $500 for motor (verified good working order) plus labor. or I can leave it the way it is and hope it doesn't die on me. (not my pick)

Input greatly appreciated, I am in Rochester, NY

 

[Bt Doctur]

could be something as simply over filled on the oil and its foaming up to a loose pickup tube for the oil pump. If this motor has had some work like a hi-volume oil pump that would give you the same no oil condition.

 

[Keithmanlite]

all I now is the boat runs great until I go above 3500 rpm. then once I let it recover it runs great until I go above 3500. Took 1/2 qt oil out, to get it within an inch of full mark on the stick. where do I start, spending unnecessary funds may knock me out of the using the boat realm

 

[NHGuy]

Take out enough oil to put it right on the top mark, an inch high will allow problems.

 

[Keithmanlite]

I just took delivery of a manual oil extractor, I will do an oil change, add 4.5 quarts and go back out.
Also found another mechanic who is willing to go out in boat with me and try and give me some guidance.
I have been told he is best I area and only works on mercruiser

 

[Bt Doctur]

While your at it, try to measure how much oil you remove. The dip stick may be reading incorrectly
I would change the filter ,add 4 1/2 qts and check the dipstick

 

[Keithmanlite]

I bought the 6.9 liter manual extractor so I should be able to gauge how much comes out. I will do as you recommend. I am concerned though because I cant pull drain plug like a car. How much do you think always gets left behind? Also found another mechanic who is willing to go out in boat with me and try and give me some guidance. I have been told he is best I area and only works on mercruiser

 

[Bondo]

I bought the 6.9 liter manual extractor so I should be able to gauge how much comes out. I will do as you recommend. I am concerned though because I cant pull drain plug like a car. How much do you think always gets left behind? Also found another mechanic who is willing to go out in boat with me and try and give me some guidance. I have been told he is best I area and only works on mercruiser

Ayuh,..... Very very little,.....

 

[Bt Doctur]

you not confusing the liters of the engine 5.7 and adding 5.7 liters of oil, are you?

 

[Keithmanlite]

spoke to a mechanic and was kinda surprised because he didn't bat an eye, just told me what was wrong.
Hence I am posting here to see what all of you think. I explained everything in the post and he stated quite simply.
"you have an air leak in the oil pump, at high rpm and heat oil becomes thicker and the pump stops pumping oil because it is sucking air instead of oil."
He did however remind me that the engine is 30 years old, and could quite likely have other problems that have not yet surfaced.
he said we could pull the engine fix pump and exhaust problem for couple hundred bucks. I will be still potentially going to experience failure of older engine components. He said if we are going to pull the motor, he could rebuild everything including carb and fix exhaust problem. new motor, no winterizing and would store boat while he is working on it. Give it back to me with 1 year guarantee Normally it would cost $1800 but if I do it over winter for potentially 30% less.

any thoughts on this, wife is skeptical, not a lot of choices right now.......................???

 

[FreeBeeTony]

To my knowledge oil gets THINNER when hot.......
Try to determine if its backfiring out of the carb
I had a similar problem around 3300RPM.....eventually found a lifter hanging up, piston finally kissed the valve and the rest is history.

I'd run it w/o the flame arrestor and the engine hatch open and see if it's spitting out of the carb in that condition.....be careful, don't put your face over the carb

Hope this helps......