fuel filter change on Universal 35B engine

[hwd]

I recently changed both my Racor and engine-mounted fuel filters on my Universal 35B engine (Catalina 34 mkII 2005).  I first changed the Racor filter element and filled the new one with injector cleaner before mounting to reduce air in the system.  Engine started up immediately and ran well.  When I changed the engine mounted spin-on filter next, I also filled it with injector cleaner before mounting.  The engine started up OK, smoked a bit from the exhaust, but after running for about 5 minutes, it began to lose power and eventually coughed out.  It starts OK, but exhaust shows smoke and the engine acts as if fuel starved and cuts out.  Is the injector cleaner causing the problem?  Should I remove the engine-mounted spin-on filter and refill it with fuel instead?  I don't think it is an air block problem...  Any suggestions would be appreciated.

[Stu Jackson]

Did you loosen the nut on the top of the secondary filter housing until fuel came out?

Experience with our M25 indicates that it is necessary to do so, perhaps the same for your engine.

Discussed in the Bleeding 101 Topic.

[Roc]

The M35B is self bleeding.  When I change the filters, I turn the key and let the fuel pump operate for 20-30 seconds (2-3 times longer than I usually wait).  Then press the start button.  Starts up with no problem after that.

[hwd]

Thanks for the quick replies.....what do you think about my question regarding the use of the injector cleaner in the engine-mounted filter...could this be causing the problem?

[Stu Jackson]

No.

[hwd]

From your replies, it sounds like you think the problem may be with air in the system,  Can I bleed the secondary filter on the engine while the engine is running?

[Ron Hill]

hwd : I'd loosen the bleed nut on the top of the engine filter and then have someone else start the engine.  When you see fuel at the bleed nut I'd tighten the nut back down.

A thought

[hwd]

Thanks, Ron....Will do.  I appreciate your help with this. 

[Stu Jackson]

You might want to reread the Critical Upgrades.  There's a post about M35 bleeding.

[Robert Mann]

Bleed it at the filter and at the injection pump just to be sure.  Get a good flow of fuel out.  Remember the fuel pump is wired to the glowplug switch so it runs while cranking when the glowplug is activated, and then it runs from the oil pressure switch.  Mine had a broken +ve wire at the pump which made it interesting.  Point regarding the pump is relevant if you are bleeding it by yourself, you may need a jumper wire from a 12v source so you get fuel pressure from the pump.

[hwd]

Robert,  Thanks for your help and suggestions.....I'll give it a try.   My problem seems to have arisen after I changed the secondary filter on the engine.   Changing the Racor was not a problem.

[Robert Mann]

I wouldn't use fuel system cleaner to prime the system when you change filters.  Either fill them with clean fuel or just bleed the system after.  Don't be afraid to let the fuel run out, just have a good supply of rags on hand.  I don't fill the filters as I always seem to spill fuel doing that, I work with the stuff everyday and I don't like the smell. 

Interesting is, even with the electric fuel pump inoperative the system will siphon enough fuel to keep the engine running at below full speed and output.  However it takes forever to bleed the system that way.

[hwd]

Thanks again for your help with this.....I'm going to the boat in the next few days and will give it a shot.