Can't go over 1300 rpms 7.4mpi

[jmarines]

What a way to celebrate our new to us boat. We purchased a 1998 24ft with a 7.4 mpi (ol061405) and it would not go over 1200 rpms. It would bog down like it was getting starved for fuel. I was able to get it back to shore but noticed it was having a difficult time cranking up after I turned it off. (Had to load it on the trailer) my first thought was maybe the fuel gauge wasn't working properly so we ran to the gas station. It only took 10 gallons before the pump clicked so I knew it wasn't a fuel shortage. What I did notice was when it topped off.. a little fuel came out of the hole.... it was yellow in color.. not sure if this was the cause of my rpms issue but I don't think it could be good. Any insight would be great guys. The previous owner said he took very good care of the boat... even produced numerous receipts for repairs. Out of frustration the wife made it clear that she wanted it dropped off at the shop to see what's going on. Well of course I listened.. happy wife.. happy life is how I see it. It's currently at rinker world here in Houston. $125 for the test ride at the lake to reproduce the issue and another $125 for them to diagnose the issue. I should have gone into marine repair...dang... anyways.. I'm enclosing a picture of the yellow fuel that came out.. maybe it's additive?

 

[alldodge]

The first thing someone should do with a new or new to you boat is change the oil, drive lube a fuel filters. Yellow coming out of the fuel tank means the gas has probably gone bad. If the gas is bad, there is no saving it, and it needs to be removed. Open the gas cap and see if the gas smells like gas.

You have cool fuel ad standard fuel water separator filter.

What have you done to the boat since your purchase?

 

[jmarines]

I haven't done anything to the boat. This was just a test run to see if everything worked as it should. I have the filters on order and oils already in the garage ready to be changed.

 

[alldodge]

I haven't done anything to the boat. This was just a test run to see if everything worked as it should. I have the filters on order and oils already in the garage ready to be changed.

Then my guess is the fuel is bad and needs to be removed. Need to look further to verify

 

[Fun Times]

What I did notice was when it topped off.. a little fuel came out of the hole.... it was yellow in color.. not sure if this was the cause of my rpms issue but I don't think it could be good.

Do you happen to know what hole it came out of? The fuel tank vent hole that some models have the vent hole right at the fuel filler neck. Should the vent line system be clogged even with fuel, It could cause issues. But that yellow staining is a sign of your diagnostic starting point.

 

[jmarines]

Fuel came out of the main fill hole where the pump is inserted. The previous owner just contacted me and said the last time it was serviced was last year. He had the outdrive serviced a few months ago due to the seals starting to leak . He had the outdrive serviced and new seals installed. He also said the last time he had it out was a few months ago . It's looking more and more like the fuel has gone bad and probably a gummed up filter as well.

 

[alldodge]

IMO, Gas doesn't go bad that fast, my guess is it hasn't been run in a long time, and the PO is giving you some of the old car salesman stories. My guess is the boat hasn't been touched in a long time, and the leak that was mentioned may have just been band aided. I would suggest get into the boat real good before taking it back out.

 

[jmarines]

Update

Shop just called... they went through the boat and found the fuel is bad. I spoke with the PO and he did say the fuel has been in there for at least a year. He said he last took it out 4 months ago and that's when he noticed the leak in the outdrive. Anyways... the shop is going to remove the fuel and change out the spark plugs...I figured they would foul due to the fuel... they wanted to change out the fuel filter and distributor and rotor along with replacing the trailer winch but I figured I could tackle those items at the house instead of paying $125 hr for them to do it . I think this shop is a little over priced but considering they have great reviews and were able to get me in the next day instead of having to wait 3 weeks like the other shops because there so far behind .. I think it's all good. $650 total and it will be ready for me to pick up this afternoon. Thanks for all the advice guys... I still consider myself a noob on boating.. but this site has helped tremendously

 

[wahlejim]

Glad to hear that the issue was found. Don't overlook the carb after fuel issues. Odds are if there is junk in the filter, something may have made it past and into the carb. While you are tackling everything else, wouldn't hurt to go through that process as well.

Also, look a the dates on the receipts that you have. Sounds like he took care of the boat up until a year ago. A lot can go wrong in a year. Tackle all of the routine maintenance items that are due, bellows every 5 years, impeller every year, in addition to what you are doing. Eventually it all becomes routine.

 

[Lou C]

One issue that many will miss because they don't even know its there, is the anti siphon valve. This is a spring loaded valve on the gas tank that the fuel hose from the pump connects to. Its purpose is to prevent gas from siphoning into the bilge in case that fuel line leaks. It looks like a fuel barb and inside there is a ball valve that is spring loaded. When you start the engine the suction developed by the fuel pump overcomes the pressure of the spring which holds the check ball against the inlet to the valve when the engine is off. If this corrodes internally, the ball can restrict fuel flow and cause exactly the problem you had. Just another thing to check if you continue to have this issue.

When trouble shooting I usually start with the ignition system and then move to the fuel system. A good test is to get a large Mason jar. Then remove the fuel filter and pour the contents into the jar and let it sit. This will tell you if there is water (forms a layer on the bottom) or other debris in the fuel). As far as ignition, not a bad idea to check the resistance of all the plug wires and take a look at the cap and rotor. If any of the wires has high resistance or the cap/rotor has any corrosion, they should be replaced.

If you want to learn how to maintain your engine/drive package yourself consider getting a factory shop manual, it will be a big help....

 

[jmarines]

Thanks for the info guys. After I brought home the boat I went ahead and replaced the cap and rotor just for piece of mind. I went ahead and order a new impeller along with a new thermostat. Should be here this coming week. I'm not waiting on these parts to install them because I had a issue with my Cooling temp when I went out this weekend. I noticed the temp rose to almost 200* then went down to 160 once the thermostat opened. I figure I would replace the impeller while I'm in the cooling system just to make sure . Anyways... boat ran great this weekend. Definantly more power than my 3.0 .. didn't get up to wot due to the family being on board and the lake was very choppy. Once I get the impeller and thermostats installed I'll be back and hopefully be able to really open her up.