Can't get more than 3000RPM out of the engines

[Boobie Trap]

Here's the deal....

2001 Monterey 302CR (545 hrs)
Twin 305 CID (5.0L) Volvo Penta's

Both engines had been running fine. I change the out-drive oil and engine oil with synthetic oil every spring, with filters and fuel filters.
We use the boat year around albeit not as much during the winter.

I filled up with gas in Feb and the next weekend could not get over 3000rom out of the either engine.
Tying it to the fuel, changed fuel filters, got some crud and water out of them both. With ~80 gallons in the tank treated the fuel with Sea Foam Gas Treatment. (4 pints).
I go out and right to 4400 RPM.

Next weekend right back to 3000 RPM. The port engine runs better and can get 3800 RPM but the left starts dying off above 2000rpm. If I shut it down and restart, it works better and after the third attempt, it will come up to 3200 rpm but after a couple of minutes, starts dying off again.
If I reduce the right throttle a little, unload the demand, the rpm comes up 200-300.
I have had the fuel lines, fuel tank checked, fuel filters changed, again, and still nothing.
I have been told that it could be the fuel but no body else has had problems with the fuel from the same marina.

Whats up? Could both fuel pumps be bad? Could the water cause damage to them both at the same time?
I just find it hard to fathom that both fuel pumps are bad a the same time. Even tho it seems the right is a little worse than the left.
The right engine also has a hard time starting after it gets warmed up and sits for a short period of time. I have to give it about 3/4 throttle to get it to crank. When cold, fires right off faster than the left. The fuel pump has also made a very high pitch whining noise but never given a problem.

Any ideas? I have ordered two fuel pump kits form Iboats and will install them Friday. The ones on there are the original pumps, I think. I have all the paper work and no mention of fuel pump replacement. Figure it can't hurt! I also plan on changing out the spark plugs while I am at it, they have about 200 hours on them. :grumpy:

Thanks

:grumpy:

 

[Boobie Trap]

Re: Can't get more than 3000RPM out of the engines

Nobody has any ideas? Someone must know more than I know which is zip, squat, nada, zilch!!!

The pumps come in today. Replace them, fuel filters, spark plugs, If that does not cure the problem, I think I might sink her!!

 

[Don S]

Re: Can't get more than 3000RPM out of the engines

What's the full model number or serial number of your engine. 305 sure doesn't tell us much.

Here is a list of possible causes of low WOT (Wide Open Throttle) rpm.

In no particular order

Engine Won't Reach Operating RPM. Check

1. Fuel condition. Type and Octane possibly old fuel
2. Propeller pitch or diameter, damaged blades
3. Restricted fuel pickup tube or anti siphon valve Fuel System Test
4. Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
5. Marine growth on hull and outdrive
6. Wrong gear ratio in outdrive
7. Restricted carburetor air intake (clogged flame arrestor)
8. Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive
9. Poor cylinder compression Compression Test
10. Carburetor defective, or wrong type.
11. Fuel pump pressure and vacuum
12. Boat overloaded, improperly loaded, or improperly trimmed.
13. Engine Overheating
14. Engine timing and ignition system operation
15. Remote control cables and linkage for proper travel to open throttle plates fully.

 

[Boobie Trap]

Re: Can't get more than 3000RPM out of the engines

Don,

Thanks for your reply.
The engines are5.0GiPEFS Model #3869057

 

[Don S]

Re: Can't get more than 3000RPM out of the engines

You need to check the fuel pressures on both pumps and I would suggest you get it hooked up to a diagnostic computer and find out if it's going into SLOW mode as well.

Fuel pressures while running should be
Low pressure pump 8?4psi
high pressure pump 29?2psi

 

[Boobie Trap]

Re: Can't get more than 3000RPM out of the engines

. Fuel condition. Type and Octane possibly old fuel
4. Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
9 Poor cylinder compression Compression Test
11. Fuel pump pressure and vacuum

Don ,
These are the only ones that could be a problem. All the others have been checked and are OK

It started on both engines at the same time, I have always had problems with the STBT eng cranking without giving it 3/4 throttle but it always ran great. The spec call for 4600-5000 ROM WOT. I have never gotten that. only about 4200 but that is not a concern. The previous owner might have replaced props with higher pitch, not sure.

The fuel is the prime suspect from the beginning. As I said the problem started right after I filled up at the marina in Feb. I suspect the fuel had been sitting all winter and not treated and was old. I was the lucky one. I have about 1/4 tank left. Waiting for the weather to improve and going to try and run most of it out before replacing pumps, filters, plugs. Then put some known good fuel in it with some Sea Foam and see what happens. I even check to make sure that I had not put diesel fuel in by mistake.

We shall see what happens and will post. The fuel pump kits are due in today so will get to work today or tomorrow and get her done!
Thanks for you help!!

 

[Boobie Trap]

Re: Can't get more than 3000RPM out of the engines

I had/have a hard time thinking that BOTH fuel pumps went out at the same time. I guess if there was an outside catalyst that contributed then it is possible. They are both 12 yrs old. That is why I am replacing them as it is time anyway.

Keep the fingers crossed. It is hard to find a person that will work on a boat. The marina sucks. They are totally unreliable and overcharge like crazy. You get a bill and all it says is the engine was repaired. Not what they did. They won't touch my boat.
If you have someone come in, the marina tries to make them bill the marina and then they tack on a 20% charge. It is robbery and I refuse to abide by their stupid, outlandish rules.

Thanks again!

 

[Don S]

Re: Can't get more than 3000RPM out of the engines

Did you look at the fuel filters and see if there is any water in them?

Why in the 'ell are you replacing fuel pumps? Do you seriously think two pumps failed the same way on two engine at the same time?

 

[Boobie Trap]

Re: Can't get more than 3000RPM out of the engines

Don,

Yes, I checked them both times for water and anything else that might be in them.
I have replace both fuel filters twice! I replaced them and the engines ran fine for one day. The next weekend, back to the same problem. I'm thinking I got some really bad gas. I changed them, again no help. The right pump has had a very high pitch whine to it for months. I am also about to retire so I'm thinking that I will, while I can afford it, go ahead and replace them both. After all, that is what all the mechanics have been telling me. I took the longer route and started with the obvious first then worked backward. It seems that the local shops wanted to replace the pumps and go that way. THAT is NOT the way to work and save any money.

I said it in the last post. I too have a hard time wrapping my head around the fact that two pumps failed at the same time. The first time I changed the fuel filters, they were half full of water and had a sufficient amount of contaminates in them both. I have added additives to the fuel. nada, zip!

Other than opening my wallet and tell someone to just fix the dam thing, I am where I am.

So to answer your question, cause I feel the hell like changing out 12 year old pumps. Can't hurt!

Thanks for your insight...

 

[Don S]

Re: Can't get more than 3000RPM out of the engines

I asked if you checked them, not changed them.
Empty it in a clear container and see if there is water in it. If the place you got gas last has water in their tanks, then you will keep getting filters full or water.

 

[Boobie Trap]

Re: Can't get more than 3000RPM out of the engines

OK and the solution was?????

I changed out the fuel filters, the old ones seemed clean when I dumped them, but I changed them anyway.
When I replaced the high pressure fuel pumps, (very easy and simple to do, 1/2 hr for both) I noticed some, what looked like paint chips, around the two lower o'rings. Looking at the bottom, at the screen filter that is built in, they were pretty much clogged with "stuff".
I replaced pumps, new fuel filters and the engines have never run so smooth. They just hum and go right to 4200 RPM.
It would appear that they were just getting starved of fuel.

Now to fix the cranking of the right engine without giving it some throttle all would be perfect!!

But it is a boat, Break Out Another Thousand!!! But if gives one pleasure!!

Thanks Don for all your help!