Volvo AQ170 to 305 Mercruiser Conversion

Joined
Apr 18, 2012
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Hi Guys, This isnt my first post. I got help with previous issues i had when i bought my boat from iboats. Any ways i bought a Pride Searaider 22ft Half Cab. She is fiited out real nice and had the volvo AQ170 motor with 270 leg. All seemed ok till i put her in the water for the first time and she started to overheat. After joining iboats forums i was told that these engines can suffer from all sorts of problems if they were not looked after correctly. The engine run great but would start to overheat on the plane and would over rev to the point of blowing. After some info from iboats and some investigating i found the strainer on the motor was rotten allowing air into the mix, also the legs steering bushes were non completely shot which also meant the seals for the water pipe were shot to. I stripped the leg and had bronze bushes made for the plastic ones and bought a complete new oring and seal kit which i replaced. After putting her back in the water i still had the issue of over revving. I found the prop which was 14" dia 15" pitch was to small so i got hold of a 15" dia 15" pitch and this got my revs at WOT to around 4700. Now she runs great and the only issues i have had is the manual fuel pump decides to start priming itself when running causing me to run out of fuel. I have solved this problem by strapping a tie wrap around the primer arm. I am looking at bypassing this with a electric pump. Max speed of the boat with this config is around 23 knots. Not a race winner by any means but gets out of the water pretty good.
I have just purchased (why i did this i dont know lol) a crate with a 305 mercruiser and Bravo 1 leg. This comes with all forward controlls steering cable, wiring etc. The 305 had recent heads and new 4 barrell and low draw starter fitted. The reason the guy was selling was he had repowered his 25ft to a new fuel injected 6.2.
I have done some research and apparently i need a transom adapter which is available for this conversion.
My question is will i see much of an improvement with this new setup? or should i sell it on to some one else?. As far as i can see i will be gaining power trim and a fair bit more grunt.
I was looking at a new project and this could be it. I paid $1500 for the motor and leg etc which i think was cheap. I intend to pull the heads from the motor to get a look inside and check condition. Maybe give her a freshen up with new shells and rings if needed.
I will upload some pics to give you an idea of the condition of the boat. The guy who owned it before me had it for 11 years and it went in the water twice. Rest of time was spent in the shed. I ended up buying it for $6500.
Looking for info from anyone who has gone from similar setups to the mercruiser.
Thanks in advance.

Clint:D
 

Lyle29464

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Re: Volvo AQ170 to 305 Mercruiser Conversion

Wow your moving too fast.

Some Volvo guy will be along a help you with the fuel problem. Then you will have a boat you can sell and get what you really want.
The 305 will be ok but not very fast and you will need a ton of parts. I would sell everything start again a bit slower and have the boat check out by a pro.
 

Don S

Honorary Moderator Emeritus
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Aug 31, 2004
Messages
62,321
Re: Volvo AQ170 to 305 Mercruiser Conversion

Do you want help to fix your Volvo, or help to install the 305. The Merc will require a new transom, as the cutout is smaller than the Volvo 270, and just filling in the gaps won't give the support.
 
Joined
Apr 18, 2012
Messages
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Re: Volvo AQ170 to 305 Mercruiser Conversion

Do you want help to fix your Volvo, or help to install the 305. The Merc will require a new transom, as the cutout is smaller than the Volvo 270, and just filling in the gaps won't give the support.

"My question is will i see much of an improvement with this new setup?" As posted in my thread.

I understand the transom hole will be bigger hence "I have done some research and apparently i need a transom adapter which is available for this conversion.".
 
Joined
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Messages
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Re: Volvo AQ170 to 305 Mercruiser Conversion

Wow your moving too fast.

Some Volvo guy will be along a help you with the fuel problem. Then you will have a boat you can sell and get what you really want.
The 305 will be ok but not very fast and you will need a ton of parts. I would sell everything start again a bit slower and have the boat check out by a pro.

The fuel problem is the pump, which i can replace, so not much of an issue there. Selling everything and starting again sounds a bit extreme. The boat is fine. The right size for me and my family. Good for fishing and cruising around on. I had the boat checked over and was told it was solid. Probably due to the fact it spent the last 11 years under covers in a shed. The motor was given a freshen up 2 years before i bought it and never saw any water.
 

Lyle29464

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Re: Volvo AQ170 to 305 Mercruiser Conversion

I can give you a wild guess. Top end will increase about 1 MPH per 10 HP. So if you go from a 170 to a 250 you will gain about 8 mph top end and about 5 at cruise.
 

Don S

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Re: Volvo AQ170 to 305 Mercruiser Conversion

Sure your going to see a difference. You are going to be going from an old 170 hp 6 cyl to a 200-220 hp V8
 
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Re: Volvo AQ170 to 305 Mercruiser Conversion

I can give you a wild guess. Top end will increase about 1 MPH per 10 HP. So if you go from a 170 to a 250 you will gain about 8 mph top end and about 5 at cruise.

Thats good enough for me. Maybe later i can stick a stroked chev in and haul ***. lol

Is the bravo 1 leg a better unit than the old volvo 270?
 
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Re: Volvo AQ170 to 305 Mercruiser Conversion

Why have i been moved from the mercruiser forum to the volvo? i am looking at info regarding the mercruiser setup.
 

Don S

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Re: Volvo AQ170 to 305 Mercruiser Conversion

The reason it's in the Volvo forum is because it's now Volvo powered. Half your original posts was about the Volvo, then a kind of "BTW, will a Merc work"?

Since you gave no info on the Merc engine, as to year or anything, thinking it has 250 hp with a carb is over exaggeration. 220 or less is realistic.

Is the bravo 1 leg a better unit than the old volvo 270?

Not really, they both have cone clutch shifting, but the Bravo does have trim.
 

Nickypoo

Petty Officer 1st Class
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Mar 21, 2012
Messages
287
Re: Volvo AQ170 to 305 Mercruiser Conversion

I don't see how selling your current boat and buying another one is any more extreme than replacing the whole engine and outdrive with a completely different setup.

The conversion is not as straightforward as you seem to think. I don't think it would be worth it especially if the current motor is in as good of condition as you say. If your engine and outdrive were shot that would be a little different.

You did ask "or should i sell it on to some one else?". I think Lyle was trying to answer that question.
 
Joined
Apr 18, 2012
Messages
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Re: Volvo AQ170 to 305 Mercruiser Conversion

OK Ok Ok , i think Lyle may of hit the nail on the head, i kinda got carried away with the prospect of running a v8 in my boat and may of jumped the gun a tad here. I have spoken to the guy i was buying the motor and leg and have agreed that i was hasty in buying it. I have lost my $100 deposit but in the long run probably saved alot more money and time. I am a mechanic by trade and wouldnt mind a bit of a project but seeing as the boat runs fine now why pull the guts out of her and start again. I suppose thats why i joined iboats.
 
Joined
Apr 18, 2012
Messages
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Re: Volvo AQ170 to 305 Mercruiser Conversion

Thanks guys, the missus says thanks. She was horrified at the thought of engine parts all over her nice patio area. I kinda thought it would be cool. I even set the time to swap the drivetrain in cases of beer. I reckoned about 10 lol or maybe that should of been 100.
 

diesel1960

Petty Officer 1st Class
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Jul 3, 2012
Messages
205
Re: Volvo AQ170 to 305 Mercruiser Conversion

I running AQ170 in my boat for years and like this engine, more fuel efficient than V8 may give you.
If you have any problems with this engine let me know.
 
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