Can't seem to figure out the problem with my 77' Searay...Please help

[semo549]

Hi everyone, I'm a new timer to this forum so I'll start by saying that I've searched these forums over and over but I can't figure out what to do.

I have a 1977' Searay, 18 foot, model srv-187. It has a mercruiser 165 in it. It has been sitting for 10 years and started up 5 years ago. Today was the 4th time this month I have taken the boat out since the long sit. Once again, the boat starts and runs good for about 10 minutes WOT, then the engine acts like it is starving for fuel. Fortunately, the boat will idle back to the dock. Everytime it does this.

Here's what I have done to the motor this year to get it ready; New fuel pump, fuel lines, fuel filter, rebuilt carb, new starter solonoid, new distributer, plugs wires, I have dwelled and timed the motor as well. Last night I removed the anti-siphon valve from the gas tank and replaced it. I was 100% sure that was the problem; then today it does it again.

I have completely ran out of ideas. I looked into the fuel tank by removing the gas gauge float and the tank looks rust free and clear of debris. Does anyone have any suggestions for me? I'm stumped. Thanks

 

[P 0 P E Y E]

Re: Can't seem to figure out the problem with my 77' Searay...Please help

A bunch of questions fill my head.

1. is it all new gas in the tank? Hope so.

2. About 5 years ago, gasoline changed in it's composition. When this change happened, it made many problems for many gasoline boats. The new gas caused contaminates and other stuff that used to be stuck in your full system to get un stuck. it mixed with water that used to stay separate. The first few tank fulls in an older boat were a real mess. (some body please link it) This might be your plight.

3. An old boat that sat a long time needs more fuel filtration. I would get a big racore if you don't have one.


4. Check your vent.

5. try running off a temporary smaller gas tank to see if the problem goes away.

6. Double check all the tune up parts you installed for proper installation and set up.

7. Check for water in the combustion chambers

8. welcome to the forum and best of luck with your challenges

 

[semo549]

Re: Can't seem to figure out the problem with my 77' Searay...Please help

Before I got the boat running I pumped about 10 gallons of old gas out. Now it has 20 gallons of new gas in it. Today I also took the gas tank vent hose off to see if that was causing any problems. That didn't help. So I guess my next step is to run the boat with an auxillary gas tank.

 

[gshldon]

Re: Can't seem to figure out the problem with my 77' Searay...Please help

i had the same problem with my boat when i bought it, i put about a half a can of seefoam in the tank and filled it with fresh gas, it ran good for a while and then it cleaned out the gunk in the carb and it ran rough for a bit, and then it cleared up and ran great and has been ever since.

I would try that and see if it works for you.

i would not run it a WOT until you work all the old gas through it

Good Luck

 

[P 0 P E Y E]

Re: Can't seem to figure out the problem with my 77' Searay...Please help

Before I got the boat running I pumped about 10 gallons of old gas out. Now it has 20 gallons of new gas in it. Today I also took the gas tank vent hose off to see if that was causing any problems. That didn't help. So I guess my next step is to run the boat with an auxillary gas tank.

Take a look at all the parts you replaced with a fresh look first.

One thing about the gas problem was that in some boats, it attacked other parts of the fuel system up steam of the tank. Are the fillers brand new?
There is also a filter at the carb where the gas line goes in.

To avoid personal injury or damage to the engine, exercise caution while working on open fuel lines and flammable liquids. Keep fire away.

Take your time and start off by checking the systems that still work to narrow down the fault.

When you think you might have found it, double check your hypothesis before replacing a part.

Good hunting

 

[ziggy]

Re: Can't seem to figure out the problem with my 77' Searay...Please help

a couple other ideas...

low compression
exhaust restriction
coil or condenser

have ya tried going through the trouble shooting guide in the service manual? them three items were out of that guide. there were more too..

 

[MikDee]

Re: Can't seem to figure out the problem with my 77' Searay...Please help

There is also a filter at the carb where the gas line goes in.
Good hunting

All Good info popeye, Yes, be sure to check this also!
One more thing, is there an inline screen in the fuel tank, aside from the antisiphon valve that needs to be checked?

 

[semo549]

Re: Can't seem to figure out the problem with my 77' Searay...Please help

well im pretty sure i figured out what the problem is. i took the float out of the tank and looked down into the hole with a flash light. it looks clean as a whistle untill i scratched the bottom of the tank with a screw driver. there is chunks of crap lining the bottom of the tank. i put a can of seafoam in there to help break it apart. not im going to drop the trailor nose to the ground and pump the gas out of the tank and hopefully all the gunk comes out with it. thanks again for the help.

 

[ken_23434]

Re: Can't seem to figure out the problem with my 77' Searay...Please help

I had nearly identicle running problems when I first got my boat running last year. It had previously sat for an unknown number of years (5+). I am certain it was old fuel "gunk" getting disolved off the fuel tank walls.

I purchased a bottle of Starbright Enzyme fuel tank cleaner (found at West Marine). This stuff is supposed to help dissolve the stuff that is getting dislodged in your tank. You dump in some of this stuff and then let it sit for atleast 24 hours.

In addition to using that stuff, I also ran an universal electric fuel pump ($30 from Autozone) downstream of my in-line fuel filter and had it discharge back into the fuel filler. I let the pump run for HOURS. I changed out the in-line filter a couple times while it was recircing the tank this way. I also would periodically grab the front of the trailer and rapidly lift and lower the boat or just rock the trailer from side to side to try and force any material to break away from the tank and get sucked up through the filter.

I did this a couple different days, one time leaving the battery on a charger with the pump running for a full 24+ hours.

The next time I took the boat out after doing that was the first time I was able to run it for any length of time at WOT without suffering a loss of power and lean engine condition.

Keep a couple extra fuel filters for your inline filter (if you don't have one install one) and when the boat starts to loose power, change out the filter and see it that fixes your problem. I know RACOR is "the brand" to have, but they are REALLY expensive. I found some brand at Wal-Mart that was under $10 per filter. I know they are not as good, but for me they were good enough (and the correct price) to help clean the bulk of the junk from my tank. After I was fairly certain the bulk of the crap was removed, I switched back to using the Mercruiser filters.

I hope this is helpful to you.