MerCruiser 228 fuel issue?

[rheacox]

Hi all,

I bought a 1983 Cobalt 19BR about a month ago and after some work, I launched it last weekend. The night I launched it, it ran great, cruised around the lake for an hour, docked it and went home.

The next morning, it took a while to crank and it didn't really want to idle. It ran well for a few hours and then it would die if I pushed it past around 2000 RPM. However, it would run fine in neutral, up to 5 grand and stay there no problem.

My uncle who is an expert mechanic said my problem was probably crap in the gas, clogged filters etc. I changed the carb filter which was filled with sand and the fuel/water separator. It took awhile to start but I figured that was due to the new separator.

That being said, I have yet to actually test it on the lake. Does anyone have suggestions of what else it could be or is crap in the fuel system the general consensus?

 

[alldodge]

Re: MerCruiser 228 fuel issue?

I see it as your uncle is correct. You found sand in the carb filter and if sand made it to that filter it must have passed the fuel/water filter. Probly has some crud in the tank which is going to need to come out somehow, either by filter changes or tank clean and flush. Pump some fuel in a container and see if there is any signs of water. Then clean the carb out good and let us know what you found.

 

[rheacox]

Re: MerCruiser 228 fuel issue?

Got out on the lake today, drove around pretty good for about 15 minutes and then started doing the same thing, dies after about 30 seconds if I push it past 1500-2000RPM. I'm not sure if it has to do with pulling crap through the fuel system or if it has to do with the engine warming up. I pulled the carb and there is silt and sludge in the bowl but its not as bad as I thought it might be. I'll get a rebuild kit, clean it out, rebuild it and put it back on the boat. After that I'll report back. Any idea where to get a rebuild kit for it? It's a Rochester Quadrajet carb.

 

[alldodge]

Re: MerCruiser 228 fuel issue?

If stuff is making it into the carb filters are not doing what they should. I did a google search and came up with this
Rochester Quadrajet Carburetor Rebuild Kits - Carburetor Parts for Rochester Quadrajet, Mercarb Marine, Carter & Ford Motorcraft Carburetors

There are probably many others

 

[rheacox]

Re: MerCruiser 228 fuel issue?

My guess is that the sediment that was in the bowl was there for awhile. I can only account for the last month of maintenance on a boat thats 30 years old, how the previous owners maintained it is anyone's guess but it seemed to be pretty decently. I ordered a rebuild kit, float and idle pickup tubes from that site, with a name like quadrajetparts.com, I'll trust them.

 

[alldodge]

Re: MerCruiser 228 fuel issue?

Hope it works out, still seams like a lack of fuel issue. Have you check the fuel pump pressue?

 

[rheacox]

Re: MerCruiser 228 fuel issue?

Funny you should mention the fuel pump. No, I didn't check the pressure but while I was cleaning the carb, I found that the brass fitting that the fuel pump vacuum hose attaches to was almost conpletely plugged. I'm assuming this could contribute to the lack of fuel problem especially at high RPM?

 

[Bondo]

Re: MerCruiser 228 fuel issue?

Funny you should mention the fuel pump. No, I didn't check the pressure but while I was cleaning the carb, I found that the brass fitting that the fuel pump vacuum hose attaches to was almost conpletely plugged. I'm assuming this could contribute to the lack of fuel problem especially at high RPM?

Ayuh,.... Welcome Aboard,.... The clearish plastic line, 'tween the fuel pump, 'n carb,..??

Naw, That's just a Sight Tube/ safety line,...
If the fuel pump diaphragm ruptures, gas goes into the carb through it, 'n ya See it,...

 

[rheacox]

Re: MerCruiser 228 fuel issue?

Gotcha, thanks. So how is the pump driven? I know it's not electric. So now I'm hoping rebuilding/new parts fix the problem. Is the fuel pump rebuild-able if the need arises? Also, how would I check the pressure and what should it be?

 

[alldodge]

Re: MerCruiser 228 fuel issue?

Pump is driven from the cam shaft though a rod which actuates it. When installing a new one you need to make sure the pump shaft fits under the rod. These pumps are not rebuildable for the most part, not economically feasible. Fuel pump pressure is measured with a tee fitting placed on line and should be 4-8 PSI.

 

[Bondo]

Re: MerCruiser 228 fuel issue?

Gotcha, thanks. So how is the pump driven? I know it's not electric. So now I'm hoping rebuilding/new parts fix the problem. Is the fuel pump rebuild-able if the need arises? Also, how would I check the pressure and what should it be?

Ayuh,.... It's driven off a cam lobe,...

It's replaceable,... pump "Kits" ain't been 'round in decades,...

Pressure should be 4 to 6 psi, at the carb's inlet,... plumb it anyway ya please,...

 

[rheacox]

Re: MerCruiser 228 fuel issue?

Ok, so it looks like the carb itself isn't the problem. Took it back out on the water today and after 15-20 minutes it started coughing and backfiring and then died. I got it going again but it started very hard and would die at anything more than a quick idle, had to get towed in... Still seems to idle alright though. The only other two things I could think of are ignition problems (timing off, bad wires, coil etc.) or gas boiling out of the carb since the problem seems to occur after the engine warms up. If it were the fuel pump, wouldn't it happen weather the engine were warm or not?

 

[Bondo]

Re: MerCruiser 228 fuel issue?

Ayuh,.... To test the fuel system, hook up a remote tank to the fuel filter/ fuel pump, 'n run it,...
That'll eliminate the tank, vent' 'n lines,...

Run without the motorbox, to test for vapor lock,...

 

[rheacox]

Re: MerCruiser 228 fuel issue?

My uncle and I did some poking around today, he thought the coil looked funny so we changed it out for the one from our old boat. The way it was running, he didn't seem to think fuel was the problem anymore. He said he thinks it could either be the distributor pickup or the ignition module.

I have a newer module from our old boat, would it be possible to retrofit it? They're both Thunderbolt IV modules but one is a big box with no connector and the other is a small block on a heatsink with a plug connector on it.

 

[rheacox]

Re: MerCruiser 228 fuel issue?

I think I might have it. By doing some non USCG approved things, I think I've determined that it's either sucking crap and clogging the line or its creating a vacuum in the tank. I took the fuel line off the pickup tube and put it in the sending unit hole. The boat ran great, held it at 3000rpm and 30mph for about 15-20 minutes and it never even hiccuped and there was no way that I could do that before. How do I clear the vent tube and/or clean the tank?

 

[NHGuy]

Re: MerCruiser 228 fuel issue?

Pull off the antisiphon valve, it's the fitting where the fuel line attaches at the top of the pickup on the tank. It could easily be your clog. It's just a ball and spring device so fuel can't fill your bilge if the fuel line ruptures below the level of the fuel in your tank. Your engine mounted fuel pump has enough suction to open it. Just take it off of there and clean it out with some carburetor cleaner. Make sure to exercise the ball & spring to assure yourself it's clear. If there's any possibility it's messed up get a new one. You have the sender out, how does the gas tank interior look. I'd say siphon out the gas since you are this far into it.
You might also want to pump out some of the fuel right through the tank pickup, there might be junk getting in there too. If the fuel flow slows down after a while figure out why. Now is the time to make sure it's going to stay clear.

 

[rheacox]

Re: MerCruiser 228 fuel issue?

The tank was surprisingly pretty clean for being 30 years old, just a couple little bits of leaves and things, very clean otherwise. I didn't take the antisiphon valve off but its working fine with 3 of the 5 bolts out of the sending unit hole so I'm pretty sure the vent tube is partially plugged up. Also, I forgot to mention that when I took the first bolt out of the sending unit, air rushed into the tank so it was definitely pulling a vacuum somehow.