Runs great for an hour and then loses power. possible fixes.

[bluefishing]

Hello,

I saw a boat for sale that caught my fancy. The owner's description in the ad is this:

"21 foot Dixie 3.7 l;iter 165hp mercurser runs good for about an hour than it seams to lose power i have replaced the fuell pump, distributor heat exchanger, coil, points, carb rebuilt even tried running gas out of a 6 gallon tank. i have given up on this boat and bought a new one. "

I know I am asking you to speculate, but the price is very good, what does the brain trust at iboats think could be the possible cause? Easy or difficult repair?

Thanks,

 

[Another retired guy]

Re: Runs great for an hour and then loses power. possible fixes.

Hi. Not a lot of info to go on, so I'll be first to rub the crystal ball
Assuming the seller has done everything he claims then one remaining possibility is that it may be heat related. Engine bay reaches a certain temperature and something doesn't like the heat?
Could be a challenge

 

[bhammer]

Re: Runs great for an hour and then loses power. possible fixes.

Who knows.... But, I can tell you that this boat has the 470 in it. Do a search here on iBoats and the web about the 470 engine. I used to own one and I loved it, but it took a lot of tender loving care and maintenance to keep it going. I also loved the day I sold it.

The 470 has some quirks:
1. You want the larger heat exchanger
2. If it has overheated, the heads can be toast real real quick
3. The alternator system on it is like a motorcycle and does not have an alternator. A lot of folks upgrade to an alternator.
4. Some parts are no longer available, or will cost you an arm and leg for them. (charging system, timing cover...)
5. The cam shaft is known to leak at the timing cover seal and will have to have the spedi sleeve fix done

 

[Don S]

Re: Runs great for an hour and then loses power. possible fixes.

Nobody should buy any boat with an unknown engine problem like that, especially a 470 that has it's own built in problems.
Of course, if the boat is something you "Must Have" just figure in a new engine and drive repower. And no, just sticking a V6 or another engine in it's place is not an easy or cheap option.
Fact is, keep looking, you have not found a boat worth having.

 

[bluefishing]

Re: Runs great for an hour and then loses power. possible fixes.

Nobody should buy any boat with an unknown engine problem like that, especially a 470 that has it's own built in problems.
Of course, if the boat is something you "Must Have" just figure in a new engine and drive repower. And no, just sticking a V6 or another engine in it's place is not an easy or cheap option.
Fact is, keep looking, you have not found a boat worth having.

Everybody, thanks for chiming in. Forgive, I an new to the i/o. If I put a v4 (not the 470, isn't there one with 180 hp?) or a v6, am I looking at just new engine mounts or a new transom due the the drive not lining up with a different motor?

this is just a question, as I truly respect Don S's opinion and am 99% sure I will walk away. I just want to know what I am up against if I repower.

 

[scott8058]

Re: Runs great for an hour and then loses power. possible fixes.

Im with the others, i would walk away from this one and as for the repowering it why would u want to replace a 470 with a 4 cyl esp on a 21ft boat. Idk what your budget is but i think you could get a good boat without the hassel. good luck