View Full Version : Unleaded fuel - 190PS 190

04-16-2008, 07:57 AM
I just bought an engine/tranny manual from Ski-Dim for my 1991 PS 190 351. It states in there that I should be using leaded fuel and can use low lead for short periods but must not use unleaded fuel. This can't be real as we haven't had leaded fuel in the UK for 15 years, and surely a lot longer that that in the US? Is this a carryover from a much older engine from the 70's or what?

04-16-2008, 08:30 AM
Unleaded fuel is like LOWFAT milk. It costs more to refine. Here in the USA we are experimenting with new fuel additives called ethanol. It suposedly costs less to make than gas, burns cleaner and costs more. I can't wait to see what my fuel bill will be this month $4.10 per gallon
yesterday for diesel...

I all seriousness. Unleaded will not hurt your motor

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04-16-2008, 10:41 AM
But 15 years ago was 1993, and that boat was made when you still had leaded gas. It won't hurt your motor. There are plenty of cars, trucks and boats from that time and they haven't had problems. I have a 1990 Chevy pickup with a 5.7L motor and it has enough miles to have gone to the Moon and most of the way back. I recently checked my compression and it ranged from 155-163 pounds. The valve seats were the reason leaded fuel was needed and that hasn't been an issue for decades.

Could just be old info that they didn't bother to change because nobody thought it was in the manual. Enjoy it, don't worry about the fuel (unless it's just bad) but as long as you don't overheat it badly or neglect the oil and filter, you'll be fine.

88 PS190
04-16-2008, 01:48 PM
Cross over from leaded in the states was earlier than 91, atleast in many areas it was.

Does your actual boat have anything stating one way or the other?

I know on my bike the PO had the heads machined for new valveseats in the late 80's because it was a leaded bike.

Some people argue that residual lead in tanks should have kept valve recession to a minimum for many years after that.

I do however wonder if there were marine engine versions designed for leaded gas sent to europe.

04-19-2008, 03:36 AM
Nope the boat doesn't have anything specific about fuel anywhere on it.

When I say unleaded hasn;t been used in the UK for ~15 years, what I mean was it was still available, but only to serve cars 10+ years old at that time. Catalysts came in in mid 80's with unleaded fuel.
I think it's just a carryover statement from an older version of the engine.

04-19-2008, 08:32 AM
Jeez, the phase-out of leaded gasoline was in the 70's wasn't it?

IIRC the two big problems with that switchover from leaded to unleaded gasoline was valve seats and catalytic converters. Leaded fuel ruined the catalytic converters, and unleaded fuel could damage the valves on older cars. The catalytic converter isn't going to be a problem on a 1991 boat, and I can't believe that that engine and those heads don't have the hardened valve seats that have been used on US engines since the early 70's.