87 2.3l Omc Wot and planning issues

[New2 boats2]

3 weeks ago, my brother bought a Capri, I have had to replace the out drive shift cable, that is working good now.

The boat will run up to full rpm with muffs, in water I hit WOT it plows water and turns only 3000 rpm.
I checked timing Found it to be set at 17* BTDC. Manual siad stock is 10* BTDC.
So I fixed that.

Also changed fuel filter and a new prop plus all oils.

The boat will get up and plane now but is sluggish.
Towing a tube is impossible.Compression is good not ideal but all cylinders are above 100lbs.

Is this just how these boats are?

Or am I missing something

Thanks in advance.

 

[southkogs]

Is the new prop the same as the old prop? What diameter and pitch did you put on? WOT should be more than 3000RPM, but I'm not sure exactly what on a Cobra.

 

[New2 boats2]

Yes new prop is the same as the old, I've been searching and can't exactly find what prop came equipped stock for this boat.

Im sure I can go down in size for the prop and get performance back, but does that fix the real issue?

 

[Speak]

Yes new prop is the same as the old, I've been searching and can't exactly find what prop came equipped stock for this boat.

Im sure I can go down in size for the prop and get performance back, but does that fix the real issue?

The Prop I use on my cobra 2.3 is a 17 pitch. Motor will turns at around 5600 if I give it the "beans". Boat will do 40mph but it's really working hard. Check if your mechanical advance is seized in the distributor? Might want to check that. Pop the cap off, under the points and condenser you will find the mechanical advance guts. Make sure it's free and allowed to swing out. Few other things to check are1. Is your choke opening fully. 2. Are u getting good fuel delivery to the carb. Fuel starvation? 3. Is your carb opening fully when control box is pushed to full? Let us know.

 

[New2 boats2]

Yes carb opens fully, and choke is working, mechanical advance distributer I will check tomorrow afternoon. And report back.

 

[New2 boats2]

So I went to a smaller pitched prop, still did the same thing. Came home checked the spark plugs, one was a little wet.

I'm going to do another set of new plugs, run it and check the plugs, if they are wet then a carb rebuild.

Anything I'm missing please let me know.

 

[Bondo]

Compression is good not ideal but all cylinders are above 100lbs.
Anything I'm missing please let me know.

Ayuh,..... Welcome Aboard,.... At 100 lbs psi compression, it's a rebuildable core motor,.....

Should be much closer to 150 psi,....

 

[New2 boats2]

Just one cylinder reads 105 which tells me that it's more likely to be valves or head gasket

 

[New2 boats2]

OK, finally got the boat back together.

I had a hard time starting it.
When it did start I could only run it at 1200 rpm then it would die. The carb air/fuel screws were both set to one and a half turns out.

So I adjusted the idle screw( the one on the throttle linkage) turned the a/f screws out to where they were set. Finally got the engine to idle down to 650 rpm.
Checked the timing its still at 10* BTDC.

I check the dist its all snug can't feel any slop in the shaft. Rpm go up timing light shows the spark is advancing. Engine runs smooth.

But here's the problem, it when I throttled back down, to nuetral the rpm hangs around 900 to 1000rpm

Then after a minute or so it creeps back down to 650.

I'm now thinking a carb rebuild. Because the a/f screws are mal adjusted to keep it running.

Sorry for the lengthy post, any thoughts are appreciated.