chevy 350 cutting out during acceleration..vapor lock?

Hey guys,
New to the boating hobby and to forums in general. I hope I've posted this question in the right spot. I've been looking for a boat for years but have been on a budget ( I know, wrong hobby, right? ) and my dad ended up in real need of money and sold me a boat for $1,OOO. The boat is an 85 conroy x-19 (glastron?) which recently had the omc 3.0 replaced by a chevy 350. I've taken the boat out twice in the last month to prep for the summer season and I've had a reoccurring problem. The boat will run awesome for about 5 hrs on the lake and then it will just cut off during acceleration like its starving for gas. The boat has during the time on the lake has been on and off doing some fishing and some slight cruising. I never rely on a boat gas gauge but it does show fuel near 1/2 a tank and there is fuel in the filter. The first time this happened I had a faulty fuel pump and replaced it. Happened again to me yesterday. I take the boat on the water at about 9 a.m. and sometime around 2 p.m it starves on me? Frustrating since I am scheduled to take it this weekend (memorial weekend). Any Ideas and/or suggestions would be much appreciated, like I said, I am a newbie and may be in need of some guidance. Thanks in advance everyone.

Re: chevy 350 cutting out during acceleration..vapor lock?

Ayuh,... Welcome Aboard,... You're doin' Good,...
Just hit the enter key, now, 'n then,... paragraphs are easier on the eyes...

I'd start at the fuel tank Vent,+ work my way to the Carb,....
It Could be vapor lockin', but I'd guess it's Crud somewhere....

Re: chevy 350 cutting out during acceleration..vapor lock?

I'll definitely keep that in mine when typing long questions lol!! Thanks for the help.
That was my first thought after seeing fuel in the fuel filter..it has gas so what is blocking it? Where is the gas tank vent located? Obviously near the tank, but outside or inside the tank?..sorry, like I said, new to boating.
If everything checks out I read on another forum to insulate the fuel line by wrapping aluminum foil around the gas line to the carb - this seems like it would heat it up quicker to me though,wouldn't it? Should I maybe wrap the line with a bigger rubber hose around it to try and insulate it? Thanks again for the help.

Re: chevy 350 cutting out during acceleration..vapor lock?

You can check if your tank vent is clogged by 'cracking' the gas cap when you are having your issue.

If the engine comes back to full song, then you have released the vacuum that was created in your tank by a clogged vent line.

P.S. A clogged vent line will not show up until you have been running for a spell...and will 'fix' itself while your engine is turned off for a period of time.

Re: chevy 350 cutting out during acceleration..vapor lock?

Can you tell us more about when it cuts out... It cuts out after 5 hrs of continuous cruising? Or, after a few hours, you stop or idle for a while and then it cuts out on acceleration? My experience with vapor lock is that is caused by heat building up in the engine compartment. Try running the blower continuously to reduce the heat in the engine compartment.

Re: chevy 350 cutting out during acceleration..vapor lock?

Thanks for the responses guys. I will try and give some more detail here.

The boat was bought after the 4cylinder omc 3.0 was swapped out to a chevy 350 about 5-6 years ago. The boat hadn't been put in water since then and had only been in water maybe once or twice in the 3 years before that so it hadn't seen activity in some time so I fully expected some problems to arise.

With that being said, then engine had never been had any use on it and after getting it started I bought the boat. It was purchased in January of 2010 and saw its first action in some time at the end of April 2010, and again yesterday May, 26 2010.

Both times the boat has run like a champ, with some slight cruising and fishing going on. The boat hasn't probably cruised for even 30 mins continuously, unless trolling while fishing. The first time out, I diagnosed it as a fuel pump problem. The pump actually was still off the 3.0, and after some observation seemed like it wasn't holding pressure as it should and probably wasn't pumping enough for the 350.

My concern is that almost the same thing occurred yesterday again. Ran beautifully ( I really am surprised at how well this boat has been running after sitting so long ) and after a day of about the same activity..the same thing. Cuts on during acceleration. I can basically idle her in to shore to trailer it, or with very minimal acceleration, but anything more she just started to cut out and kill the engine.
Thx again guys..

Re: chevy 350 cutting out during acceleration..vapor lock?

I had a similar problem, what I did was carry 5' of the correct 3/8 fuel line and a clean can full of gas. When mine "cut out" I removed fuel pump inlet hose, stuck fresh gas hose on and off I went. Mine was a faulty fuel guage. Said I had more than I did. Also I had water in my tank I found out. This test helped me to learn no matter how much good fuel you put on water it will still get you in trouble. I also mounted a clear inline fuel filter to mine so I can keep an eye on things.

Good luck

Re: chevy 350 cutting out during acceleration..vapor lock?

I think we were both typing at the same time. I had the exact se problem years ago in a VIP ski boat. Wasps and bugs in the fuel tank. Would idle around but starve for fuel. I don't know how they got in the tank but I cleaned out prob 20 bugs. Ran perfect after that

Re: chevy 350 cutting out during acceleration..vapor lock?

You're correct, Conroy was Glastron's "economy" line of boats. They cut a few corners to reduce costs, to appeal to a broader base of boaters. Things like metalflake, multi layered gelcoats were dropped in favor of paint and/or vinyl stripes, etc. Your Conroy X-19 will be almost identical to my '84 Glastron SX-190.
Here's a sales brochure page;
http://www.classicglastron.com/85gl-ssv195-sx180-190.html

I believe vapor lock is somewhat rare in a boat, especially an I/O. There's no tranny, PS, A/C and engine rad stacked together in front of the engine to intensify the heat. And an I/O has the whole lake to draw heat away.

Re: chevy 350 cutting out during acceleration..vapor lock?

You usually only get vapor lock after you turn off and the heat soak to the fuel line occurs.

Re: chevy 350 cutting out during acceleration..vapor lock?

Seems most of the responses seem not to think that vapor lock is the issue. I agree I don't think there is too much engine heat in the compartment. I will try the gas cap trick if it happens again this weekend.
I don't wanna seem like too much of a newbie, but what and where should I be looking at for this fuel vent? I will have some time to take a look tomorrow and I will give it a good look over. Any other ideas for what I should look for? I do have a clear fuel filter, and everything appears clean - maybe the fuel gauge really is off by a bunch - wouldn't the fuel filter be pretty empty though?
Thanks for the brochure page also- yep - pretty close except mine has seats behind the two front ones also. The sales brochure was interesting, I've had more trouble finding info on the 85 conroy X19 than anticipated. I'm usually pretty good finding things on the net- guess there's a lot of boats out there lol. Thx again guys for any help.

Re: chevy 350 cutting out during acceleration..vapor lock?

ponyyboyy said:

Seems most of the responses seem not to think that vapor lock is the issue. I agree I don't think there is too much engine heat in the compartment. I will try the gas cap trick if it happens again this weekend.
I don't wanna seem like too much of a newbie, but what and where should I be looking at for this fuel vent? I will have some time to take a look tomorrow and I will give it a good look over. Any other ideas for what I should look for? I do have a clear fuel filter, and everything appears clean - maybe the fuel gauge really is off by a bunch - wouldn't the fuel filter be pretty empty though?
Thanks for the brochure page also- yep - pretty close except mine has seats behind the two front ones also. The sales brochure was interesting, I've had more trouble finding info on the 85 conroy X19 than anticipated. I'm usually pretty good finding things on the net- guess there's a lot of boats out there lol. Thx again guys for any help.

Click to expand...

I hate to go here, but...where is your "clear" fuel filter?

If this is plastic, then it is illegal to have in the engine bay of a I/O. What you need for a lot of reasons (E-10 being the major one) is a inline fuel/water seperator similar to the Racor. There are many brands of these filters a lot cheaper than Racor, and can be found even at a Wal Mart.

Here is a good article telling you all that you need to know about these:

http://continuouswave.com/whaler/reference/fuelFilter.pdf

Re: chevy 350 cutting out during acceleration..vapor lock?

Rocky road, I surely did not know they were illegal . Makes sinse though. Luckily mine is one of those aluminium/glass deals with a removeble screen. I hope it's leagal

Re: chevy 350 cutting out during acceleration..vapor lock?

Tommywalton said:

Rocky road, I surely did not know they were illegal . Makes sinse though. Luckily mine is one of those aluminium/glass deals with a removeble screen. I hope it's leagal

Click to expand...

Glass may be included as a 'no-no', you may want to research this.

My understanding is that anything that can fail from heat, or breakage, and allow raw fuel into the engine bay cannot be used. Racor makes a clear sight bowl on some of their filters that is clearly labeled for 'outboard use only'.

If you consider what would take place if the glass broke, you would probably agree that it shouldn't be near a hot engine compartment.

Someone will surely jump in and straighten me out, if I am wrong!

Happy boating!

Re: chevy 350 cutting out during acceleration..vapor lock?

Hey guys,
Thanks for your help. Yes indeed I do have the glass type also with the removable screen..and yes I think it is illegal. If I remember right it was added after the regular filter to be able to have a look at what was happening..i.e. out of gas or dirty gas. I wasn't aware of all the different type of filters and that was an interesting article..thx.
I'm gonna get a good look at the boat today and post later, thx for the help. Any advice on this Gas vent/screen? thx again guys