Need a 280 Guru's help!!

[skywagon]

I was just hoping to get some help on my plug fouling 2002 model 280. Just to give you a little history; It's on my Allison grandsport and it has 16 hours since new. I have read all of the info on it 2 times now with the DDT and it is out of breakin. I'm running 40:1 ratio merc oil and Super Unleaded. I have tried several different flavors of NGK and Champion sparkplugs: BR8hs's, bpz8hn-10's, Buzhs, QL77CC's etc.

With a new set of plugs it runs great up to full RPM(7750) and all over the RPM range for about 20 min. Then it starts running rough. When I come to a stop and check the plugs generally #1 and #5 are wet fouled. It pretty much does this regardless of how I trim it at slow speed and regardless of how long the no wake zones are.

Trouble shooting I have done: tried different plugs, oil and gas. Checked the DDT for fault codes and breakin. Checked inlet throttle blade gap and TPI settings, Checked compression and removed fuel rail and injectors to see if they were spraying or leaking under pressure. I just swaped #1/2 and 5/6 injectors to see if the plug fouling follows the injector. I have not had a chance to run it yet.

If anyone has any suggestions please feel free to chime in. I need to get this thing running well for the summer!!

[blkmtrfan]

Originally posted by skywagon
I just swaped #1/2 and 5/6 injectors to see if the plug fouling follows the injector. I have not had a chance to run it yet.

I am real curious to see what happens with this swap. I ended up just replacing all of my injectors (my merc guy gave them to me on warranty exchange) and now it seems to be fine.

BTW, before I had my richness problems, my plugs were the original set (a little over 20 hours) without any fouling.

I hope you find your problem with this test.

[RB in NM]

Sounds like the same thing that waz happenin' to Fishinfireman over on the Allison site a while back. But I don't know the outcome.
You may wanna drop him a line, he's a cool guy, he'll help ya.

RB

[skywagon]

thanks for the response guys. I'll keep you posted on the results of the injector swap.

Blkmtrfan...what plugs did you end up running and what gap? Also, how long did you have to run the fuel pump to build pressure in the fuel rail? Do you have to run it for more than a few seconds to see if any injectors are leaking by?

Also, does anybody know the proper procedure for "back flushing an injector?"

Thanks again,
Bill

[blkmtrfan]

Running standard Champions QL77CC's

Pressure built right away and started squirting in less than a second.

Back flushing was described to me as taking some small pieces of hose attached to the fuel rail, put the injectors on backwards (put nozzel end into the small hose you just put on the fuel rail) and fire them one at a time with the DDT. I didn't try it but it makes sence

Good luck and keep us posted

[Redbullet]

Denso IFW24 plugs will cure the problem.

[skywagon]

Redbullet,

Where do you get your denso plugs? I went to sparkplugs.com and couldn't find the part number. Plus, no body in town has them. How do you get yours? thanks for the reply!!

[skywagon]

Blkmtrfan,

What do you gap your plugs to? I talked to Tony Brucato yesterday and he said that it didn't sound like an injector problem...might be ignition. He said that the 280's have notoriously weak ignitions at low rpm's and that I should try closing down the spark plug gap to around .030.

I'm going to try to run the boat today with the injectors swapped if I can get out of work early enough.

Thanks,
Bill

[W. Tripp]

go to www.sparkplugs.com and type in iwf24 into the part number search. I have been buying Denso plugs from them for years.

I would recomend calling them first to see if they have the plugs in stock - the online ordering will not tell you if it is out of stock. It generally take 3-4 days for them to get the plugs in.

[blkmtrfan]

Originally posted by skywagon
Blkmtrfan, What do you gap your plugs to?

Do be honest, during my last go around with the fuel all over and fouling plugs within minutes, the plugs that are in there now were just stuck in as they came out of the package, but have now run fine for about an hour (although no high RPM runs as the whole family was with me last time). I should pull them out and check the gap

Originally posted by skywagon
I talked to Tony Brucato yesterday and he said that it didn't sound like an injector problem...might be ignition. He said that the 280's have notoriously weak ignitions at low rpm's and that I should try closing down the spark plug gap to around .030.

Does is clean up at higher RPM? What about swaping coils to see if that makes a difference?

Maybe it is just me, but I don't see how changing the type of plugs will make that much of a difference if you are fouling them so quickly

[skywagon]

Merc,

I double checked the butterfly last night and it was still at .007" gap that is recommended by my less than adequate service manual. I don't have a ddt but when I checked the TPI 2 weeks ago it was at .81. The range is supposed to be .80 to .82, again according to my service manual. I'm going to try to run the boat today after work and see if the fouling follows the injectors or if it stays with each cylinder.

Thanks,
Bill

[skywagon]

Well, I ran the boat on friday with injectors 1&2 and 5&6 swapped and this is what I found. The fouling did follow the injector to #2 and left #1 clean. On 5&6 though, it still fouled #5. I'm not sure what that means yet. Maybe I have a bad injector and a bad coil. I will put a fresh set of plugs in it this week and swap a coil to find out. If anyone has any suggestions please let me know.

Thanks,
Bill

[skywagon]

So I called Tony Brucato to talk to him about it and he suggested that I send in my complete set of injectors for him to test. He called me yesterday after checking them, I only sent them on thursday, and said "Bill, we have a problem."

Seems as though 5 out of the 6 injectors were faulty from the manufacturer. One injector was flowing 3 times what it should have at idle and 2 times what was specified at RPM. The rest of the injectors were flowing as much as 65% more than specified. He has flowed the intire set and graphed them for me. All for just $35.

Needless to say, I have a new set of injectors on the way, already pre-flowed by Brucato. His prices on injectors are extremely competative also.

I'll be testing the boat out on the water this weekend looking for a difinitive conclusion. I'll keep you all posted.

[blkmtrfan]

It is amazing that it ran at all, It is totally cool that you found you problem, can't wait to hear how good it runs now

[skywagon]

Well, I put the new injectors in from Brucato yesterday. Put in a cheap set of champions and then ran it on the hose. Well, the thing came right to life and it runs/sounds completely different than it ever has. Really smooth.

So, I decided to test my luck and dragged it to the lake. Ran about 10 gallons through it. Full throttle, lots of idle, crusing...you name it. I couldn't get the thing to even begin to run rough. This thing idles almost as smooth as a new 225X!! The biggest thing I'm excited about is that I've got that mid range punch back...just like my 260. After an hour or so of running I pulled it out of the lake and checked my plugs. Even with the champions, there wasn't a single plug that even looked remotely black....All nice and tan.

I'm going to run it on the same plugs a couple more times before I call it "done," but this sure looks promising.

Thanks again for all the help, and if you ever have a question or need for injector work CALL TONY BRUCATO!!!!! HE WILL SAVE YOU TIME AND MONEY.

Bill