On this page you will find articles on different aspects of engine care and performance. At the bottom, you will find a form for submitting questions to us pertaining to engine problems. If you do have an engine problem you would like help with, and submit it, please fill out the form as thoroughly as possible.Also, please be aware that the procedures, techniques, and other material on this page, as well as answers to your engine questions, may not work for your particular application, and in some instances, may be hazardous. It is up to you to use your own judgment as to whether information you find here will work for you. With that said, lets get to this months article.
A few answers to the most asked questions.
This month, we decided to post some answers to the questions we get asked the most, whether its on the net, or at the shop.
Oil additives.
Are super slick oil additives, like Slick 50, good to run in marine engines?Not necessarily. Most of the oil additives out there use Teflon, or other friction reducing agents, which may cause problems. If you want to use an oil additive, then those not containing Teflon would be the best choice. Why? Dupont, who makes Teflon, does not recommend using it in engines.
Another problem with oil additives, is that most marine engines don't run hot enough for them to do any good. Most of the additives work best at 180 degrees or more. Also, they may actually interfere in the detergent qualities of the oil they are mixed with, due to low engine temperature.
Our advise. Stay with a good, name brand oil, and change it often. We prefer a single weight oil of SAE 30 or 40, with 30 wt. oil being preferred. Marine engines usually don't run hot enough to get any benefit from 40 wt. oil, and can actually suffer from poor oil flow through the engine because of thicker oil due to low engine temperature.What type of lube should I run in my V-Drive?
For most applications, 85W140 will work well in most V-Drives. There are a few drives that use Automatic Transmission fluid however, and you should check with the manufacturer for your particular drive. The main thing here, is to make sure the oil is changed regularly. Just like an engine, the drive needs clean oil to operate efficiently, and live a long life.
As far as additives, again we can not recommend using an additive. We haven't done our own independent testing, and won't. We feel there is no need to with the present gear lubes on the market already.
One other thing, V-Drives can get water contamination very quickly, so check the oil often. Also, look for any metal particles. This can save a lot of time and money by catching a small problem before it becomes a big one.Can I put Electronic Fuel Injection on my present engine?
Yes and No. You can put EFI on your engine, as long as it was designed for marine application. Putting and automotive EFI on a marine engine can have some unpredictable problems. First, its not designed for the elements, water and hard jolts, that a boat faces. Second, a marine engine operates under a whole different set of conditions, than an automotive engine. Also, the sensors, especially the O2 sensor, may not like the marine environment.
A good quality EFI designed for marine use is a great add on. Power, fuel economy, and reliability are all enhanced by it. There are some good units out there, and they don't cost much more than a tunnel ram and two fours.What size prop do I need?
That's a big question, one that requires a lot of information to answer. Like: what are the engine performance figures, the drive ratio, hull type, hull length, etc..
We get asked this question allot, and most people don't send in nearly enough information. Also, guesstimating your engine performance doesn't do us any good either.
Generally, if your making lots of torque at lower RPM, a steeper pitch and lower overdrive works best. If your making lots of horsepower at high RPM a shallower pitch at higher overdrive is best. The prop diameter is critical also. The prop diameter is going to determine how well your boat is going to run by allowing enough slippage out of the hole to get engine RPM up where it needs to be. A smaller prop will let the engine rev higher at the start, and a larger prop will slip less. This is analogous to the torque converter on a car. The smaller the converter, the greater the stall speed.
Always use a steel prop for RPM of 4000 and above. A bronze one might scatter at RPMs higher than that.
A tip on starters.
This past weekend, my starter decided to fail at a location far away from the boat ramp. Worst of all, it failed after I stopped to help some folks who were having problems of their own. After I had gotten another boat to tow them, and they had departed, I was now needing a tow, but no one was in sight. So, it was get out the oar and row.
This is the second starter I have had to replace in two years. The cause of the failure is always the same, shorted winding due to heat. This time, I didn't send the core back, instead, I kept it to be rewound. Why? The starters these days are good at cranking over an engine with a compression ratio of 8.5 to 1 or less, the present day compression ratio. They don't last very long trying to start an engine with 10.5 to 1 or higher. A good facility that rewinds starters can rewind it for a high compression engine, making it last considerably longer. Its a great deal less expensive than a high performance starter from a mail order catalog, or speed shop. They can usually be rewound for $50 or less.That's all for this month. We'll try to get the Big Block Chevy project up on the site as soon as possible. We're sorry for the delay, but as with most things, the unexpected always rears its ugly head when you least expect it.
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