1994 SNOB with TBI - no start when hot

[freddyksnob]

Hello everyone. I picked up my pristine 94 SNOB this summer. 390 hours. It has the TBI EFI system. Had been in storage in a "winterized" state for 3 seasons prior to my purchasing it. I have put maybe 10 hours on it, but have been chasing this no start issue all summer. I treated the existing fuel hoping maybe no start issue was due to residual bad gas, but problem continues. Took it to a local shop and they determined low pressure pump faulty, so I had that replaced last week. Yesterday, once again - middle of the lake with everyone aboard - no start!! Ugh!!

When cold, boat starts right up, purrrs like a kitten and runs like a raped ape - 50 mph+. Once warm, let it sit for 5 minutes and poof - no start.

I removed air cleaner and there is no fuel. I removed spark plug and there is definitely spark. With all the wires, coil packs, etc I am not sure where to start with this.

I have read earlier posts about possible relays etc being faulty, but I am wondering if I should scrap the entire fuel system and simply mount a high pressure pump in the tank? How important is the water separator? Could that go bye bye?

Furthermore, I am wondering what anyone thinks about scraping the entire Pro Boss thing, in favor of a $700 Fitech TBI? I put one on my 75 Bronco and it was super easy to install and has been extremely reliable. Thoughts???

[Skidave]

Call Vince at Discount Inboard Marine. He will be an excellent source of support and probably has a conversion kit ready.

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[JGordon210T]

Most likely vapor locked. Upgrade the fuel system. https://www.nautiqueparts.com/product/retro-fcc-kit/

[freddyksnob]

Thank you for the tip Skidave. I spoke with Vince and his is a wealth of knowledge! Yes, he has a fuel conversion kit that it sounds like might fix my fuel issue

https://www.skidim.com/KIT-RETRO-PUM...info/RF080023/

I will update how this works out

[gary s]

You said you have a 94 TBI setup,those above retrokits are for 95 and up GT40 MPI. Do you have separate coil packs too?

[Tom_H]

If it's a 94 TBI, it would have the Protec with the coil packs. Your issue certainly sounds like vapor lock, but I've never really known that to be much of a problem on that particular engine. If you had a Mercruiser of that vintage, then absolutely.

However, to confirm or rule it out, the next time it happens, soak a rag in cold water (cooler water or lake) and put it on the fuel pump/lines. If it fires up, then you have a vapor lock issue and may be able to solve it with some insulation on the fuel lines, running the blower when you're stopped, or propping open the dog house to cool it down in there.

Your TBI unit doesn't take as high of pressure as a multi-port system would, so I wouldn't think the FCC retro kit would work.

You might consider just replacing all your fuel lines as well, as given the age, they're likely not ethanol safe (if you've been using any gas with ethanol), and it's possible they're internally collapsing when they warm up and get more pliable