Ongoing engine troubles...New engine?

[1990 Conbrio]

Hey all, I just joined the forum.

I have a '90 Supra Conbrio. I am the only owner. The engine has only 254 hours. Every summer I have problems where the engine doesn't start; the engine cranks but doesn't turn over, or the engine doesn't even crank. I've tried different mechanics and the results seem the same.

The engine has some rust on it, but I am told that is normal.

I am the point of either selling the boat or looking for a new engine.

Anyone else have these issues? Could it be the engine is a lemon?

Thanks.

[michael hunter]

Its either ignition , fuel or mechanical . These engines are not all that complicated. First what ignition do you have in it ? Is it carbureted? What is the mechanics that have worked on it say about the problem? Where is the boat?

[1990 Conbrio]

Its either ignition , fuel or mechanical . These engines are not all that complicated. First what ignition do you have in it ? Is it carbureted? What is the mechanics that have worked on it say about the problem? Where is the boat?

It is carbureted. Not sure of the ignition...The mechanics say "it rode great when we tested it." Very frustrating...

[leetudor]

It is carbureted. Not sure of the ignition...The mechanics say "it rode great when we tested it." Very frustrating...

Go out with the techs and see how they operate the boat and see for yourself their results.

[crystal waters]

Have 89 conbrio with just over 900 hours . Same engine . 351 ford windsor PCM with Holley 4 barrel carb. Runs great, always has!
Have you winterized your motor each winter in terms of lay up until spring? Did you fog your engine and carb?
Did you put fuel stabilizer in your gas at the same time?
Hoping your carb isnt gummed up etc!
That said is your carb pumping correctly?
Is your ignition timed correctly , how are your points and plugs?
Have you had your coil checked?
Find a qualified marine mechanic and pay a few dollars to have the motor gone over.
Much cheaper than a new engine and at 254 hours it is virtually new!

[1990 Conbrio]

Have 89 conbrio with just over 900 hours . Same engine . 351 ford windsor PCM with Holley 4 barrel carb. Runs great, always has!
Have you winterized your motor each winter in terms of lay up until spring? Did you fog your engine and carb?
Did you put fuel stabilizer in your gas at the same time?
Hoping your carb isnt gummed up etc!
That said is your carb pumping correctly?
Is your ignition timed correctly , how are your points and plugs?
Have you had your coil checked?
Find a qualified marine mechanic and pay a few dollars to have the motor gone over.
Much cheaper than a new engine and at 254 hours it is virtually new!

It's been winterized every year by local marinas. I have zero mechanical ability...:(
I have new tech coming out Monday and will hit him with all these issues.
I will add fuel stabilizer.

Thank you.

[CJD]

I have owned a lot of boats. When it comes to carbureted boats, you either need some mechanical ability or have a decent mechanic (very hard to find).

If you aren't up to tinkering, I'd look for a fuel injected boat. They start and they run. If they don't, they tell the mechanic what is wrong...he replaces it and it starts and runs again!

[crystal waters]

I concur with CJD in terms of making sure you use only a qualified mechanic in your case .
Having zero mechanical apptitude makes you totally dependent on such an individual so hire a good one !
When i bought my first inboard I too had zip for mechanical knowledge but learned as time moved along and now can do a fair amount on my own , diagnose virtually any issue and hire a qualified marine mechanic to do what I know I cannot.
I admire your honesty re zero knowledge but poke your nose into the upcoming diagosis and repair and learn some basics. Not that hard.
Good luck!

[cadunkle]

Since the problem is intermittent you're going to have to learn the basics and do some testing. It's either fuel or spark if it otherwise runs great when it does run. Wouldn't hurt to rebuild the carb. These old Holleys are simple and rebuild kits are around $50. Good weekend project to take it apart, clean everything, and reassemble.

I am leaning towards ignition though. If it cranks and cranks but doesn't even try to start I suspect bad coil, points (or electronic pickup) or wiring flakey. Get a multimeter and test for approx 12 volts at the coil + terminal with key on when it won't start. May have a ballast resistor that typically drops a couple volts off, but should not be under maybe 9v-10v key on engine off. Check this when it won't start. No voltage, you have a wiring problem. If you have voltage check for spark. Bring a spare spark plug and pull a plug wire, put on the plug, and hold the wire by the boot pushing the ground strap of the plug tight against a good ground (any raw metal surface/bolt/etc. on the engine). Have someone crank it over while doing this, you should see a strong spark (hot, white or light colored. Head a strong snap/crack). No spark or weak spark (yellow/orange, quiet snap) may be a sign of a weak ignition coil, low coil voltage, dirty or maladjusted points, failing ignition module or low voltage to ignition module. Check voltage at various points (batteries, ignition switch, starter/solenoid at engine, etc.) and clean connections with a wire brush or sandpaper.

Intermittent problem, in my experience, are often electrical in nature and unfortunately can be tricky to diagnose.

[wotan2525]

Time for you to buy a mechanics tool set (I like craftsman) and start learning about engines. These are simple engines with lots of online information available. I'd start with some basic tune-up parts: plugs, filters, wires, rotor and cap. Then I'd check timing and I'd rebuild the carb.

It will run great after that. And you'll learn a lot. And you won't be at the mercy of dodgy mechanics.

Entire project from start to finish? Including some online research? 10-15 hours.

[CJD]

But, it's MUCH more fun buying a new, fuel injected boat!!

[1990 Conbrio]

Have 89 conbrio with just over 900 hours . Same engine . 351 ford windsor PCM with Holley 4 barrel carb. Runs great, always has!
Have you winterized your motor each winter in terms of lay up until spring? Did you fog your engine and carb?
Did you put fuel stabilizer in your gas at the same time?
Hoping your carb isnt gummed up etc!
That said is your carb pumping correctly?
Is your ignition timed correctly , how are your points and plugs?
Have you had your coil checked?
Find a qualified marine mechanic and pay a few dollars to have the motor gone over.
Much cheaper than a new engine and at 254 hours it is virtually new!

Looks like it was the coil- this is what's the mechanic told me: "Coil wire to the distributor wire is green. No spark. No spark at the coil. Been green there for a while. Recommending a tune up kit."

[crystal waters]

GO for it and let me know how it runs afterward!

[1990 Conbrio]

GO for it and let me know how it runs afterward!
That's the plan..he is going to do it Tuesday. Thanks all.

[jasun]

Classic supras.... Making mechanics out of boaters every day!


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[Moor]

I have owned a lot of boats. When it comes to carbureted boats, you either need some mechanical ability or have a decent mechanic (very hard to find).

If you aren't up to tinkering, I'd look for a fuel injected boat. They start and they run. If they don't, they tell the mechanic what is wrong...he replaces it and it starts and runs again!

I have to somewhat disagree with this. I've owned 4 boats, 2 inboards, all were carburated engines. If the carb is in good condition, and tuned properly to the engine, they work perfect. Granted, im very comfortable with tuning carbs, once they are right, they do not need to be tinkered with. I haven't touched the carb on my supra in over 2 years, and it runs perfect. Winterize it properly, use ethanol free gas, and you shouldn't have any problems with a properly set up carb. I do agree that a modern fuel injected engine is more trouble free. But i wouldn't recommend finding a different boat over it. Maybe a different mechanic....

[crystal waters]

So how did the tune up and new coil work out?

[SquamInboards]

If the new coil/tune-up does solve the problem, don't assume it's the only problem.

A boat of that age with only 254 hours tells me you don't use it that much. This actually may not be good thing, depending on what kind of environment the boat lives in. Sitting for long periods of time in a damp environment isn't good for any mechanical or electrical system. Just my 2 cents...

However, I do agree with those above who have said that there's no reason it can't work perfectly for you. But maybe it sits for 2-3 weeks in between when you use it? I don't know, but since you said sometimes it doesn't even crank, that sounds like the battery is either weak, or the connections are weak/corroded, or it's sitting for too long in between being run.

[crystal waters]

So 1990 CONBRIO ---- how did things work out for you after the tune up etc?
Interested to hear from you?