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Please Help 88 OMC Cobra low power under load

C

captsully

Member
"1988 Bayliner Cuddy (1952

"1988 Bayliner Cuddy (1952CK) with OMC Cobra 5.0/4V (chevy 305).

I bought the boat in the fall after taking it for a test run. The boat jumped out of the water and quickly hit 55 MPH at around 4200 RPMs.

Since then, I have had the outdrive serviced/engine aligned, new distributor cap/rotor/points, plug wires, and plugs. Also new exhaust manifolds, riser, bellows, fuel filter and oil filter and oil. I also sprayed a crap load of carb cleaner through the carb and even let it sit for an hour with pure Seafoam (cleaner) in there. So...I thought I had cleaned out the carb good.

I put the boat in the water today and set the timing with the engine in forward idle gear. I set it at 9 degrees BTDC (one of my manuals says 8 BTDC and the other says 10 BTDC---I split the difference).

The engine sounds great with drive disengaged--not missing at all. Very responsive and revs up easily over 4500 RPMs (I didnt push it). I took it out past the no-wake and tried to open it up, but it had very little power. It slowly picks up speed and tops out at 33 MPH and 3000 RPMs. It seemed to be starved for fuel? I had some autolite plugs in there...but today I bought some NGK and that didnt help.

To recap...with drive disengaged (neutral), the engine is running SUPER! With drive engaged (under load), it only hits 3K RPMs/30MPH and very sluggish.

PLEASE HELP! I am supposed to take my family to Solomon's Island on Wednesday for 3-days of boating.

Thanks all!!
Sully"
 
"Not sure I have an ESA issue?

"Not sure I have an ESA issue? Isnt that the module that allows easy transition in/out of neutral? If so, I'm not having issues there.

I only have issues with low power when under load. The engine is not instantly responsive, like it was in the fall. And it wont get over 3000 RPMs/30 MPH."
 
"When the ESA shift interupt s

"When the ESA shift interupt switch is made it interupts the ignition system causing the engine to "stumble". This takes torque off of the drive mainly to aid in shifting out of gear. If your cables are improperly adjusted or binding, the SI switch could be remaining closed therefore grounding the ingition and causing a "stumble" or "miss". It is easy to check and worth your time to eliminate it from the equation.}"
 
"I need the ESA module to be a

"I need the ESA module to be attached in order to put it in and out of gear though. So...to troubleshoot it, would I need to be in the water in forward gear, then remove the wire leading to the ESA and then open up the throttle to see if it is bad?"
 
"You actually can do some test

"You actually can do some testing out of the water. Look at the picture in the following post.
http://www.marineengine.com/discus/messages/12488/171187.shtml

The shift interupt switch is circled in yellow. Look at your switch with shifter in neutral. The roller should be center in the "V" of the actuator lever. With engine "OFF" shift the drive into forward gear and look at the switch again. It should still be in the "V". If the roller is not in the V but instead is on one of the "peaks" the switch is made. If this checks out it may require checking in the water. Do that by unplugging the connector before heading out. Shifting into gear should not be a problem. Be sure idle speed is correct. See if the engine runs normal. If it does, you've found your problem. You can still shift to neutral it just may be a little hard. Another option is to kill the engine then shift to neutral."
 
I have about 1 hour of light l

I have about 1 hour of light left...and I actually would like to try this tonight (along with a 20 minute ride to the river). I'm taking my laptop outside now to troubleshoot (wirelessly).

Please keep in touch!

Thanks!
Sully
 
"We may be onto something here

"We may be onto something here.

The roller is in the V when in neutral. The engine is OFF. I pushed the drive handle forward into gear and the roller is now on one of the peaks (NOT still in the V).

You previous post said this means the "switch is made". Does this mean I am done troubleshooting and simply need to replace the switch?

Or do I need to do more troubleshooting to confirm?

Specifically, is there something I can do right now to verify (i.e. defeat/bybass the switch and run my boat in water)?

Thanks!
Sully"
 
"BTW...I dont see how the roll

"BTW...I dont see how the roller could stay in the V?? When you push the gear handle forward into gear, the "V" must move. The roller appears to be steady. Therefore, how can the roller stay in the V with it in forward gear?"
 
"Yes, Run it in the water like

"Yes, Run it in the water like I said above with the connector to the ESA module unplugged to confirm this was the problem. Get back with us afterwards."
 
"Binding of the lower shift ca

"Binding of the lower shift cable is what causes the lever to move and make the switch. Once in gear the bind should be gone allowing the lever to relax to it's home position, therefore releasing the switch."
 
"Unfortunately, I am out of ti

"Unfortunately, I am out of time for this evening. It will be dark by the time I get to the river...and I am too much of a newbie to know how to boat in the dark.

But what you are telling me at this point is that the ESA module/switch appears to be bad based on this out of water (engine off) test. Next step is to test in water with switch defeated/unplugged. I assume I will notice some difficulty with getting the engine into gear...but what I HOPE to see is better performance (i.e. higher RPMs/Speed). Correct?

I see 4 wires coming out of the back of this switch (2 black and 2 blue). The go into a black connector (with wire holding clip) which converts the 4 wires to 2 (1 blue 1 black). Do I simply disconnect this black connector to disable the switch for this test?


Thanks again!
Mark"
 
"OK, here's the deal. We

"OK, here's the deal. We have an indication that the SI switch may be staying made (roller on top of peak). Testing on the water with the switch disabled will prove (or disprove) this. Do this by removing the wire clip and unplug the connector. Launch the boat and test run it. I don't expect you will have any difficulty shifting INTO gear. If the problem still exists we are back to square one. If the engine runs normally you have narrowed this problem down. This DOES NOT mean the ESA or the switch is bad. They are doing their job! What it would mean is you either have a bad lower shift cable, improperly adjusted cables, or possibly the actuator lever is not working freely.

Now, in your description of the connector you located you said "4 wires coming out of the back of this switch (2 black and 2 blue). The go into a black connector (with wire holding clip) which converts the 4 wires to 2 (1 blue 1 black)".
Look at the connector again. Where you saw two wires (one blue one black) is there also a loop of blue wire on that side of the connector? If not you probably have the new style ESA which is supposed to have a built in timer that only allows the ESA to work for 6-7 seconds. If that's the case we may be barking up the wrong tree."
 
"Were you having this problem

"Were you having this problem before all the tune up work and carb cleaning, or did you have this work done to try to solve this problem?"
 
There is a blue loop as well..

There is a blue loop as well....I forgot to mention it. Very sorry....I do not want to waste your time at all.

I was NOT having this problem prior to my tune-up actions. The one-and-only time that I ever drove it was with the mechanic the day I bought it. It ran almost perfect (except it maxed out at only 55 MPH at 4200 RPMs).

What about the outdrive servicing and engine alignment? Do they mess with the lower shift cable or anything else?
 
"Just a word of caution when d

"Just a word of caution when doing the static put in gear test so you don't go down the garden path. There will be a bind in the cable causing the switch activator to move and stay up (or down, depending on which gear you selected) because it hasn't completed going into gear yet. If you do this test it is best done with someone at the prop to turn it which will allow it to actually complete the going into gear sequence. You could do this with the motor running at home on a hose with muffs. Big Caution though, either remove the prop or somehow block the back of the boat from anyone getting too close."
 
"Chuck,
You had me thinking a

"Chuck,
You had me thinking about cables/adjustments. I just remembered that I had to remove a cable bracket in order to get the valve covers free. Look at this picture (of my engine)http://rides.webshots.com/photo/2607592510102484116MYKYkQ?vhost=rides

I removed the gray bracket holding RED cable on the right. I put it back like it was. But if this a precision adjustment...than I screwed it up. What do you think?

thanks!
Sully"
 
"Good to hear about the blue l

"Good to hear about the blue loop. Hope is still alive!
To align the engine the outdrive would have to be off. Did they replace the lower cable? If not, it would have been a good idea. If they did, you may need to return it to them for adjustment.
Do the in-water test and see what happens. Hopefully we are on to the problem and you will see a good result. In a pinch, you can operate the boat with the ESA disabled for a day or two. It's just tough to get the drive out of gear without it and it's hard on the cables. Make sure your idle speed is where it should be. I think around 550-650 for that engine (in gear).
You might want to check your plug wires for correct order. Sometimes crossing two of them wont show a problem at "no load".
Good luck and let us know how it goes.
By the way, 55 ain't bad for that boat. Especially at 4200 RPMs!"
 
Bob makes a good point. You m

Bob makes a good point. You may want to try the test again with someone turning the prop as he suggests. I actually thought about that but I've done this test on my own Cobra a few times and never had to turn the prop. The switch always returns. It would however help solidify this theory.
Really cant tell much about the picture. If you simply removed the bracket and put it back as it was it shouldn't have hurt the adjustment. But you never know.........
 
They definitely had the outdri

They definitely had the outdrive off...I saw it. But I do not believe they replaced anything. Heck...I asked them to replace the bellows while it was off and they didnt. Pissed me off.

I checked the firing order about 10 times...really. I even had a neighbor (mechanic) verify it for me. I originally was having issues with timing until I found out that I had the points bar spring in wrong. That cleared up that problem right away.

I hope to do the testing tomorrow AM. If I cant figure it out...I will be forced to allow the marine mechanic (a new location for me) to take a go at it. I just hope they can find the problem and fix it same day. Wishful thinking.
 
"Mark...the gray brkt in your

"Mark...the gray brkt in your picture is holding the throttle cable on, nothing to do with your problem, your upper and lower shift cables are on the left side (in the picture). Easiest way to eliminate the ESA as a possiblity is to unplug the 4 pin connector as previously mentioned, worst case is it will be a little harder to pull out of gear.

I know you've checked the firing order but you can't just mess 1 wire up so you would have been running on 6 and that would have been pretty obvious. I would test that each cylinder is actually firing by running it in neutral and using a pair of insulated pliers or gloves pull each spark plug wire off one at a time and listen for the rpms to drop when it comes off and then pick back up when you put it back on. If one doesn't do this then you could have a (new) bad wire or plug."
 
"I disabled the ESA module and

"I disabled the ESA module and it had no effect today....however, with just me in the boat I did hit 4000 RPMs and 35 MPH just now (with and without the ESA)."
 
"If I am at NO-WAKE and I open

"If I am at NO-WAKE and I open the throttle completely, it bogs out big time and slowly picks up speed. SUCKS!

Looking at the troublshooting list...and after I rule out the items I already verified....I'm left with the following items to check. Being that I did not mess with the carb (other than spray cleaner) and it was running great in the fall...I am leaning towards the NEW parts I replaced (timing system).

[*]Restricted fuel pickup tube or anti siphon valve Fuel System Test
[*]Restricted carburetor air intake (clogged flame arrestor)
[*]Poor cylinder compression Compression Test
[*]Carburetor defective, or wrong type.
[*]Fuel pump pressure and vacuum
[*]Engine timing and ignition system operation
[*]Remote control cables and linkage for proper travel to open throttle plates fully."
 
"Hey again Mark,
What is the

"Hey again Mark,
What is the model number on your engine?
One thing I notice is you said you set the timing at 9deg BTDC. According to my manual for an 88 model the timing should be set a 5deg BTDC unless you are running 89 Octane or higher fuel. 89 model is 10 deg BTDC.
I also noticed that you have pictures of the timing advance mechanism. Looks like you cleaned it up so I'm assuming you checked that it is working freely?"
 
"VICTORY....the boat is runnin

"VICTORY....the boat is running at about 97%.

Here's what I found:
1. Number 6 spark plug wire (NEW) defective (grounding out)--compression on 6 cylinder good.
2. Number 8 spark plug wire (NEW) defective (grounding out)--compression on 8 cylinder good.
3. Carb gummed up

Here's what I did:
I replaced all the spark plug wires just to be safe and ran a half a can of seafoam carb cleaner through the carb. It is very responsive and fast now. I hit 4200 RPMs and 50 MPH. It does not LAUNCH out of the water...but it does jump pretty hard without bogging down.

Here's what's left to do:
1. Reset idle/timing. Dont know how to check/set dwell.
2. I have a 14 1/4 x 21 prop on there now. I am sure if I drop that down to a 19 I can get a few hundred more RPMs and get a better whole-shot to pull skiers.

I also got my first compliment on my boat....by an actual boat mechanic at the Marina. He actually stopped working on a boat and walked all the way over to tell me that my boat looked awesome. Wow...that was nice.

Here is my restoration photo album: http://rides.webshots.com/album/561348175yADjFQ?vhost=rides

Thanks everyone....finally time to enjoy my boat!!!!

Sully"
 
"Well Mark....you may not know

"Well Mark....you may not know how to check or set the dwell but you do seem to know how to handle a buffer....great job on the gelcoat in your pics!!!

You need a dwell meter to check and set those points, you can do it with a feeler gauge but I much prefer using the meter, only after you set them do you check and adjust the timing as they have a direct relationship."
 
"Mark, off the original subjec

"Mark, off the original subject for a second. I have a 1990 Bayliner Cuddy that I picked up to restore. I just finished tuning up the engine and was going to start on the gel coat. You did an awesome job removing the oxidation on yours. Would you help me with the process and recommend a product?"
 
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