Is it possible to replace fuel pump

2001 Tiara 3100 Open 8.1 Crusaders. Is it possible to replace the low pressure fuel pump on the port engine without pulling the engine?

yes its possible....the access your installation has will determine the effort required...

I'd be working by 'feel', probably positioned by laying on top of the engine. It seems the gas lines would be the biggest problem. Another "Who designed this?"

"Working by feel" is kind of a fact of life with the small engine rooms implied by twin gas powered V-8s. (If the boat were smaller they would not fit, if it were bigger we would have diesels.) If you find you cannot get it done laying on the engine and working by feel, their are several steps to consider before pulling the engine. In my case the problem was an oil cooler stuck low on the hull side of the block but the answer is likely the same. You can remove the alternator to create some additional space. Next try draining the coolant and removing the exhaust manifold on that side. That will give you even more room. Finally, just pull the head. It is amazing how easy access to side of the block becomes once that is off!

Of course now you are looking at new gaskets for the elbow and the head and if you are going that far you should send the head out to be flattened and get a valve job. And since the intake manifold and everything associated with it are already off and the coolant has been drained, it is a quick job to pull the head on the other side and get a valve job there (got to make them match!). And if the elbows are anything close to due, since they are off you can put new ones on both sides as well. You will also find the job easier if you put on new exhaust hoses as the old ones will be really stiff and cracked. Then, of course, the same stuff will look to need doing on the other engine, either right away or on next year's to-do list. Ain't boating fun?

The whole thing reminds me of the time I ended up gutting and rebuilding a kitchen that started when wifey said "Honey, one burner on the stove is not working."

Oh, and be sure to bring down a small rug or piece of carpeting to lay across the engine and provide some comfort when you are working. That was the most important lesson I learned in doing this fix.

Given the challenge of changing out the left pressure switch, it is not unusual to find the fuel pump "hot wired" to the ignition circuit. This practice compromises design safety and is not recommended - but sure is tempting when the big ones are running !! Don't do it.

@Mulletwagon Well, we just saw a post from someone that lost an engine (See "Disaster" post) due to an oil line to the filter failure,. The engine seized because there was not an oil pressure kill switch (it had a mechanical fuel pump). So it can happen and your advice is sound.

Still, I would bet that 95% of the time that this feature saves an engine the owner let it run dry of oil by not checking levels before each use. Catastrophic failures of oil lines or pumps must be rare. I think marine converted V-8s have run for many many years without the cut off switch. So if I could hot wire the fuel pump oil pressure switch, check my oil levels regularly and still go fishing I would do so. I suppose it could also be important to turn the ignition off it the engine quits for some other reason but who does not do that? Fix it when you can but the risk seems small if the choice is no boating.

Just my thoughts on the matter.

Hey Cabo, all true. Another reason for the pressure switch is to ensure a ruptured fuel line will not spray fuel in the engine compartment after the engine stalls. Thiis same concept is designed into cars to avoid gas spray following a wreck. If hot wiring the pump is necessary to get home, understanding the system and (as you indicated) being prepared to kill the ignition due to oil pressure loss or fuel leak is a biggie. Obviously always best to do the job right and optimize safety.

@Mulletwagon I see your point. I have always (wrongly) thought of that switch as an engine protection device. And it might be if it works fast enough. In any case we got along without it for years. But the real purpose is to restore the inherent safety of a mechanical fuel pump that quits along with the engine. So I agree, if it is not a "get home" emergency, better (and mandatory) to get it fixed. No one needs a bilge full of gasoline.

CaboJohn, you are right, removing the exhaust elbow would greatly increase the room to move but in itself is a job, and the elbows are good. Instead I was thin enough (5'11" x 175#) to access from above (with the recommended pad) over the engine for some nuts and squeeze around in front of the engine to access the fuel lines and the other nuts. Mission accomplished! 2 hours but with this experience it should only be a one hour job max. Thanks for your reply.

Glad you can get back to boating. Congratulations!