'88 268 Sundancer - was fine, but now wont plane

[joeinbend]

Hi all,
I recently bought a 1988 268 Sundancer, runs the Mercruiser 454 with Alpha 1 outdrive, 401 hours. Our first weekend out, everything was flawless, she had plenty of power and would get on a plane at about 3200 rpm.

We took it out a week later, and started having some odd problems. The first thing that happened was, as we were leaving the dock, I realized the outdrive trim would not go all the way down. After fiddling with it and finally deciding to turn around and trailer it for a better look, the drive went down, and we were able to take off. We were loaded down pretty good with gear, so i wasnt suprised that I couldnt plane out, and wasnt really trying, as we werent going very far.

When we pulled into where we were camping, I saw the bilge was dumping fluid out the side, which was red/brown in color. yikes!!! Popped the cover, and saw there was in fact fluid down there. First thing in the morning I refilled the resivour of the trim pump with fluid.

When we took it out for the first run in in the morning, it was not getting anywhere near planing out, although the the outdrive was all the way down (and visually confirmed that it was in fact down), and the engine was dogging out at about 2700 rpm, topping out at 9 mph (gps).

Later I went out by myself, no gear on board, and was able to get it to about 2900 rpm, and just on the edge of planing out, topping out at about 14 mph (on gps).

I know there has to be a correlation between the fluid leak and what I am experencing, but I'm too new with this boat to have an idea of what is going on.

I am also thinking that for there to have been enough fluid dumped in the bilge to trigger the float bilge pump, that must have been a lot! Maybe it wasnt the trim hydraulic fluid that was leaking??

 

[SCORPIO]

Did it bog down or did it spit and pop? I would start with fuel filters and check engine timing. Is your flame arrestor clean? Are the throttle plates actually opening fully? Is the choke stuck? If this just started suddenly, it sounds like something simple. Prehaps the dist. advance is stuck. The only red colored fluids I can think of besides the trim fluid would be powersteering and trim tab fluid, both automatic trans fluid. If your PS pump siezed, you would break the belt and smell buring rubber.
Maybe time for a tune up.

Just a thought, could the shift interruptor switch be stuck on? That would rob you of power.

 

[joeinbend]

There was no popping or misfiring, it just sort of acts like there should be more throttle. when it's in neutral, it will go all the way up to 5000+ RPM. Where can I locate the choke? I do not have a choke on the dash, so I am assuming it is automatic. The flame arrestor is clean.

I am also unfamiliar with the shift interrupter switch, can you expand upon that?

 

[SCORPIO]

The choke is the large flat metal plate that will be visable withthe flame arrestor removed. Its on the top of the carb and it is automatic, the older ones used a bimetal spring in the top of the manifold and a rod connected from that spring to the choke plate. When the engine is cold, the plate will be closed to allowing for a richer mixture to aid in cold starting and performance. As the engine warms up, the spring expands and opens the choke to the verticle position allowing more air to enter the carb. and lean the mixture to what a hot engine requires. If the choke sticks closed, it will restrict air flow and produce poor high speed performance and usually black smoke caused by too rich a mixture. Causes can be gum on the linkage or the rod may be disconnected or jammed.

The shift interruptor is a small switch located on the starboard riser. Its operated by the shift cables. It causes the engine to stumble momentairly while shifting to make the outdrive shift smoother. Bad or misadjusted shift cables can cause the switch to stay on for longer than required. Usually this is most noticed at slow speed (idle) when shifting causing the engine to stall while shifting. My old boat (with an OMC outdrive) had the shift interruptor go bad and it would stay engaged continuously. It ran rough, had low power and would not plane.

Could be a fuel issue too. Maybe clogged fuel filter (check the one in the carb inlet, its small and plugs easily) or restricted intake screen or anti-siphon valve.

 

[joeinbend]

I did some more in-depth diagnostics tonight, i hooked up the elephant ears so i could run it for a while, and I found the plug wire from the coil to the distributor was arc'ing back to one of the posts on the coil itself. From my experience with car engines (mostly Ford), this is 100% our culprit. I'll install new plug wires this week and while I'm in there i'll go ahead and do new plugs.

Plug wire question: are there "over the counter" plug wires for the Merc 454 that are the right length, available at your auto parts store? I realize this is a Chevy 454 block, but I ask the question because on my race boat which has a Ford 460, I always have to do the cut to length style.

 

[SCORPIO]

I thought it would be something simple. West Marine sells ready made wire sets for various engines. Glad you found the problem.

 

[mwph]

Glad you found an easy enough fix for the coil/wire problem but I still have two questions.

1.) Would this coil problem only show itself while in gear but run fine in neutral? I can understand adifference being under load but those RPM numbers seem huge.

2.) Plugs & wires are great but what about the fluid in the bilge?

 

[JDW]

NAPA has a list of marine parts. I use their wires on my 454 block and they work just fine.
While you are putting in new plugs and wires you might as well put in a new rotor and distributor cap. I also put in an MSD coil to give a little larger spark in the cylinder to be sure I burn all the fuel.
You may have to add a resistor block with a larger coil but that is a very simple thing to do.

jd

 

[joeinbend]

Hey all, This is a really old thread, but I figured I had better follow up (I hate dead-end threads!). The problem with low power/RPM response / lack of planing out was in fact bad plug wires. As stated above, one of the wires was arcing back to the block.

The leaking fluid was hydraulic fluid from the OD trim. there was a small crack in the fluid reservoir, which I replaced, and have had a completely dry bilge since then. yesterday I took her out of storage and de-winterized her, a good cleaning inside and out, and a couple hours out on a local lake to "stretch her legs", and everything is running great! Happy boating season everyone, and especially to my friends here in the Northern states where we've had way too long of a winter!!!

 

[djhawi]

Hey Joe
I have the same boat here in Hawaii
Do you happen to know the length of you Shift cable that runs from your control box to the moter

 

[joeinbend]

I'm afraid I don't have that information, however I bet if you post that question as a new topic under the Classic Sea Rays forum, you will get an answer pretty quickly. Good luck!