Still no power

[Dan01543]

So I got a 1996 wellcraft excel 21sl boat with a volvo penta 5.0fl motor. I have no power after 2000rpms. This is what has been replaced.
Spark plug wires and spark plugs
Cap and rotor
Ignition coil
Carburetor has been completely rebuild with a holley rebuild kit.
New starter and alternator
Fuel filter replaced and fresh fuel.
I have check my timing and it's dead on where it's supposed to be at I've check for crossed spark plug wires and everything is fine.at a idle or in gear on the trailer it runs fine but in the water after 2000rpms runs very rough and is still backfiring out the carburetor. Now again the carburetor is completely rebuild. The fuel pump also has fuel pressure. So I'm now completely out of my mind on what else it could be. I really need someone's help that know volvo penta 5.0fl motors very well because I don't know what else it could be. So can someone please help me out.thank you

 

[alldodge]

Serial number?

 

[Dan01543]

4110137196 is my serial number

 

[alldodge]

Is the firing order correct?
Should be 1-5-4-2-6-3-7-8 and rotor turns CCW

 

[Dan01543]

Yes

 

[alldodge]

Motors are fairly simple and yours is perfect.

Fuel pressure, timing (firing order on 5.0 is different then 5.0 HO), compression, compression, voltage all perfect, so guess I got nothing.

Sorry but hope another can help

 

[Dan01543]

What would cause backfire out the carburetor?

 

[alldodge]

Incorrect valve adjustment so the intake does not fully close and is slightly open
Incorrect timing and or firing order
At high rpm, usually about 2K, can be from a carb going lean

 

[Dan01543]

Would it be possible that might my timing chain is stretched and it jumped a tooth and it is causing it to run bad after 2000 RPM in the water.or could my entire distributor be no good since it's 20 years old. It does have a brand new ignition coil in it with alot of other new tune up parts. So meaning the distributor can't keep up with everything being new.

 

[alldodge]

If timing is not correct there can be backfire

The old fords used nylon coated timing gears and the coating can break off. If it did, that could be the issue. Dont see a all steel gear jumping

To verify remove valve cover and crank motor over watching valves and timing mark on damper.

 

[Dan01543]

Ok thank you I will look into that

 

[dubs283]

Have you verified the timing is advancing properly with rpm increase?

 

[Lou C]

check an often missed cause:
corroded or clogged up anti siphon valve on the fuel tank. Follow the fuel line from the filter/pump back to the tank, where the line attaches to the tank, that barbed fitting is the anti siphon valve. My boat had this problem about 20 years ago.

 

[ripjmk]

I concur with Dubs, check that the advance weights in the distributor are not corroded and are free to move.

 

[Dan01543]

Hi so I have a 1996 ford 302cu.in. 5.0fl motor and I was wondering did them motors have the nylon coated cam gears.if so then I definitely found my problem with no power after 2000rpms and backfire out the carburetor. Please if anyone can let me know I'd appreciate it. Thank u

 

[itsathepete]

Hi so I have a 1996 ford 302cu.in. 5.0fl motor and I was wondering did them motors have the nylon coated cam gears.if so then I definitely found my problem with no power after 2000rpms and backfire out the carburetor. Please if anyone can let me know I'd appreciate it. Thank u

Did you find evidence of cam gear coating being damaged? If so, you've answered your own question

 

[Dan01543]

No but someone else on here told me they used nylon coated cam gears so im trying to find out if that's my problem because I've checked everything else I could check and it's all fine.im getting to the point of buying a new motor if I can't find out what's wrong with it

 

[alldodge]

No but someone else on here told me they used nylon coated cam gears so im trying to find out if that's my problem because I've checked everything else I could check and it's all fine.im getting to the point of buying a new motor if I can't find out what's wrong with it

I said they did use them but I didn't say they used them on your motor. All it takes is removing the timing chain cover to verify

 

[Dan01543]

I understand but it's alot of work to take the timing chain cover off.which is why I'm asking I don't want to have to go that far with doing all the work unless I know for sure that they did.alot of money has been spent already trying to guess what is going on and I don't want to have to go through all the trouble of taking something apart to find out that it wasn't it to have to spend more money putting something back together. This is why I'm asking if they did or not because if they used nylon coated camshaft gears back in 1996 then I'll buy the parts to do the job.but I don't want to take something apart if I don't have to.its a waste of time and money that I don't really have right now to be doing unless I'm for sure they did in that year. Again is why I'm asking this question on hear to be certain at first.

 

[Scott06]

Have you done a compression test ?