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Help! Whats wrong with my boat?

F

Forbin

Member
Ok folks I just got it out of the shop with a tune up and clean carb. Put the boat it today and this is what happened:

1976 Crestliner with OMC 165hp inboard

Started no problem, got gas at marina and headed out on the lake. Was cruising at about 2500 rpms with no problem then I increased the throttle and just started to to move a bit fast and all of the sudden it felt like I was tied to a dock and a rope was pulling my boat to a stop. I to off the throttle and let it idle a bit then I hit the throttle again and it was moving for about 1 min and then bam! The same thing it just pulled right back. This happened a few time to the point where I had to head back to the marina going very very slow. I could no longer even get it going medium speed without the boat pulling and chugging along.

Under the steering wheel there is a tube going from the gas tank and around to the engine in the back. In the middle of the tube is a plastic or glass tube inwhich you can see the fuel in it. When the boat is off the tube has 1/2 fuel and 1/2 air. When I start the boat it is solid fuel. When I am driving the boat and experiencing a pulling feeling I look under an dit looks like air bubbles going through that glass tube. Is that normal?​


Is it the fuel pump, or is there a leak. What do you guys think?
​
 
it is a popular troubleshooting method for folks to connect a 5 gallon outboard fuel can to the engine fuel pump to eliminate inboard tank issues.

Not sure if a 1976 would have an anti siphon valve at the fuel tank pickup, but if clogged, one of those can certainly cause a restriction. The tank vent can also get plugged by mud dawber wasps.

that sight glass affair sounds dangerous and unlawful - and it might be the problem too
 
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1) connect outboard fuel can
2) Check Fuel Filter
3) Check anti siphon valve
4) Check Tank vent

Any other suggestions? Should I check fuel pump pressure?
 
thats glass tube is connected to the fuel pump ? Or inline ?

If it sorta a glass jar then it's a sight glass and if gas is in it then the fuel pump went.

You sure it's not a inline fuel filter ? If yes that got to go.

Your onboard tank is a portable tank or a below the deck tank ?

Where is it located in the front of the boat ?

How far from the tank to the motor ?

By the way who did the tune up, he run it ?
 
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Ok I just checked! It is an inline fuel filter. It looks just like picture below. It is filled with gas. Again I can drive at 2500 Rpm then when I try to go faster my boat just slows right down and chugs. Should this be filled with gas or air? or both?
inline_filter.jpg
 
I will have to check to see if the it is connected to the fuel pump or inline. It is right at the front by the tank and the engine and fuel pump are way in the back.
My tank is not portable it is in the front under the bow below the deck. The tank is about 7feet from the engine. I just added fuel stabilizer. Yes after the tune up was done they ran it. I also had it out once before and ran it with no problems. But this time I was cruizing for about 15min when it happened.
 
Do I replace the inline fuel filter or do I get rid of it? If I get rid of it how do I clamp the fuel line together where the filter use to be? Also why was it there in the first place if I don't need it?

Also why am I putting my spare prop on the boat? What does that have to do with anything? I just got a new prop for my boat.

No it is not overheating. There is a heavy gas smell in the boat though.
 
It is an old boat and an old gas tank. I thought the purpose of the filter was to stop any sediment or dirt from the tank from getting into the motor? Or would most sediment/dirt just get trapped in the anti syphoning valve?
 
It ain't legal or safe. Get rid of the inline filter. Even of you got to replace all the hose.

There is a filter in the fitting that enters your carb.

There is a filter in your fuel pump.

If you want to can test it 4-7 psi no less and no more.
 
Chiefalen! Thank you very much for all your help! I will remove the inline filter and check everything else and I hope that is the problem.

Cheers
 
Just one more question! Someone else said I should replace the inline fuel filter with a fuel/water separator with a spin off filter should I do this or just get rid of it?
 
don't put any fuel filters near the tank or under the dash
that's comical that your boat had a lawn mower fuel filter on it.... those things are great for mowers up to about 25HP
moeller.jpg


If you want to buy a MARINE water sep. fuel filter, go ahead- never a bad idea
the instructions that come with it will tell you where and how to install it.
 
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you say there is a heavy gas smell in the boat correct? that spells real bad trouble in any case. i think you should check and see if you have a marine fuel pump or auto fuel pump . if an auto pump is there , replace with a marine fuel pump. since there was lawn mover parts on your fuel line im guessing the previuos owner has other incorrect parts in there as well...dimitri...p .s. im no expert , but id say you better look closely at whats really going on with your fuel system before something bad happens
 
I second the supply system checking.

You definitely don't want to be smelling any petrol fumes anytime.

With the bubbles you are referring to as the revs increase, then combining that with the fuel smell, I an tipping that you have a fuel leak between the filter and the tank. More suction from higher pump requirements means more fuel being drawn through the filter, and the pickup in the tank should be only delivering fuel, not air.

Bruce.
 
Here is an update and another issue. I check the fuel line, all valves, changed all filters and put in a fuel/water separator. I then took it out and the initial problem where it was pulling has stopped. The boat ran great. Then this happened:

When I would stop and sit for a bit then restart it would immediately start but then stop. Then I would start the boat and it would run in neutral but as soon as I put it into gear to move it, it would quit again. Finally I could get it going. Why is this happening?

Also after I got it started it seemed like it was struggling to plain out. The boat began the day great and slowly started to get worse. When driving back to the marina I had the throttle down in a set position but the rpms kept fluctuating. At one point it felt like it was struggling at 2400rpm, then it would slow down to 2000rpm and then it would start running really nice up to 3000rpm. all this with out touching the throttle. Then when I got back to the dock and slowed right down the motor just stopped again.

I had the Carb checked and the marina said it was fine.

What would cause this to happen or is it the carb?
 
Sounds to me like a partial fuel blockage.

Stalling when putting it into gear sounds like a separate problem, but could be either electrical, or simply not sufficient idle speed to carry the revolutions. When you said it would quit, do you mean it stalled, or simply stopped as though the ignition was turned off?

But, how did they check the carby at the marina? Pull it to pieces?

Bruce.
 
I mean I start it up and push it out of neutral and it stops. Ya I guess like I turned the key off not like it stalls. Then I start it up again and before I can put it into drive it stops again. Then I give it some gas and turn it over and it goes but as soon as I get close to the dock and slow down it stops again.
 
Ok folks I am still trying to figure out this boat so here is an update.
Electrical is all good. I am cruizing at 14v. Took the boat in and they cleane dthe carb and found lots of stuff in it. They didn't do a carb kit becuase they weren't sure how much I wante dto spend. Anyhow I took the boat out and it seems alot better. Drove it for an hour or so (fast, slow everything) Then drove for about 29min to a spot. Turned motor off and sat for 2hours just chillin. Then started it up and it went good for about 20minutes then it felt like it was bogged down and ther was some exhaust smoke coming out. It ran crapy all the way back to the marine and there was smoke. Not alot but enough. I though my engine was being flooded with fuel or that one of my cylinders were not fireing?? Do I need a complete carb kit?? I don't know! Anyone have an idea.
Thanks
 
Boats are a pain in the ass, judging by the age of your boat id assume there is alot of sediment in the tank, It wouldnt hurt to do a whole carb rebuild kit, your looking at roughly 100 bucks give or take for a rebuild kit, although its been awhile since ive purchased one. i know the feeling fix one thing it works but something else happens, i have horrible luck with anything with a combustion engine. But it seemed once they took apart your carb and cleaned it, it ran well so id start there. I hope all goes well, wish i had a boat that was operational
 
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