1996 22' Guardian Re-power Twin 115

Optimizing the performance of Boston Whaler boats
Siraneng
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Joined: Tue Aug 01, 2017 6:30 am

1996 22' Guardian Re-power Twin 115

Postby Siraneng » Tue Aug 01, 2017 7:09 am

Hi.

We have a 1996 22' Guardian. It is powered by twin 2003 Yamaha LF115 engines. The engines have gotten to the point where fuel pollution in the oil, though managed for a number of years is now at the point where a full rebuild is going to be cost prohibitive.

We would like to fit twin engines again to the boat, but I am aware that the twin LF115 engines combined are already 108-lbs heavier than the maximum transom weight.

I am looking at fitting twin Yamaha 90's which would then come in at a combined weight of 14-lbs lighter than the maximum transom weight.

Given the reduction in over 100-lbs in weight and the improved performance of modern engines, does this seem a reasonable repower? Can anyone advise on other options.

Thanks

jimh
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Re: 1996 22' Guardian Twin 115s repower

Postby jimh » Thu Aug 03, 2017 9:54 pm

I had a short time underway on a REVENGE 22 with twin 90-HP four-stroke-power-cycle engines. The REVENGE is a heavier boat than an OUTRAGE 22, so I suspect that the hull weight was about the same as the GUARDIAN 22, also a heavier boat than an OUTRAGE 22.

The twin 90-HP were Honda engines, and they gave a good account of themselves. The boat got up on plane and ran nicely. I would have serious doubt that you could ever get on plane with only one engine.

Also, I think the maximum transom weight for a 1996 GUARDIAN 22 was 720-lbs. Is that what you are going by?

Cf.:

http://continuouswave.com/ubb/Forum4/HTML/002449.html

Siraneng
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Joined: Tue Aug 01, 2017 6:30 am

Re: 1996 22' Guardian Twin 115s repower

Postby Siraneng » Fri Aug 04, 2017 2:42 am

Thanks Jim.

Yes, our transom weight is 726-lbs. The boat is only used currently for short trips from cold. Hence the 115's rarely make temperature resulting in the deterioration of its performance and the dilution of fuel in oil. It is used in a saltwater environment, but rarely in any serious conditions where you would need to punch through a wave.

I feel that the 90's would probably get it on a plane as effectively as the 115's due to new engine technologies and a lighter boat, and run at higher temperatures due to the loading, which is essentially what we need in our usage to get the best out of them.

Jefecinco
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Re: 1996 22' Guardian Twin 115s repower

Postby Jefecinco » Fri Aug 04, 2017 9:53 am

For the future you may want to consider longer warm up times for the replacement engines. Is it possible to install higher temperature thermostats in the engines? I would expect that cold weather thermostats would almost be a requirement for engines operated in very cold water. The new engines have some very strict emissions limitations which may require higher operating temperatures. Perhaps the newest generations are equipped with "cold Water" thermostats out of the box.
Butch

Siraneng
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Joined: Tue Aug 01, 2017 6:30 am

Re: 1996 22' Guardian Twin 115s repower

Postby Siraneng » Fri Aug 04, 2017 10:48 am

Thanks for this. We have ran with different thermostats on the 115s and a different grade of oil to prolong their life, but now their time is at an end.

Unfortunately the boat is generally used from cold, in warm waters (20 to 30-degree-C saltwater, across anchorages for five or 10 minutes. There is rarely an opportunity to open them up to get it fully loaded and temperatures up. We will consider different thermostat on any new engines.

Shadburke
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Joined: Tue Dec 12, 2017 10:34 pm

Re: 1996 22' Guardian Re-power Twin 115

Postby Shadburke » Tue Dec 12, 2017 10:48 pm

The best engine for a Guardian 22 open transom or Whaler Drive is a single 558-lbs Yamaha F300.

I have run several single Yamaha four0stroke engines on both Whaler 22 Guardian open and Whaler Drive configurations, and the lighter the motor on the stern, the better the boat performs.

Currently, I have a Yamaha F350 on a 22 Guardian Whaler Drive Divemaster and preferred the previous motor set-up of the Yamaha F300.